Probably not, no. It costs more than you actually get out of it, is what I've heard from people who have tried. You're better off participating in #ComicBookHour and #webcomicchat on Twitter (100% free!) or maybe investing in Project Wonderful ads, though I'm no expert on that.

I've tried facebook ads. The more you put into it the more you get out of it. I put 1$ in a day for 4 days just for page likes. It was estimated i would get a total of 4-10 likes based on the content and appropriate categories and age group. And i got 6 so. It wasnt off. I havent tried the other advertising features i was trying it out to see how it worked.

I originally release my comic on Facebook. Don't bother with the paid sponsoring. To begin with, there's a strict rule about the text vs graphic ratio of the post you are sponsoring, and comic pages rarely fit into that. Then, the few times I tried it, I got no actual interaction with my page. I mean, you see that a lot of people see the ad, but not a single one bothered to actually click, comment, like or anything, nor they checked any other page in the album.
It's been nearly two years since the last time I tried it, So I can't say taht I'm 100% updated, but I haven't seen anything that suggests that things are different.

Facebook's not a bad place to have a web presence (it's a good way to get your real life friends into your comics, especially) ... but you should never pay to advertise on Facebook because it's a bit of a scam. Here's why (without getting too complicated):

There are two main ways to advertise with Facebook, and both are bad.

1) Advertise to get more followers.

If you do this, then Facebook WILL get you many more followers, and quickly. However, no matter what areas and demographics you target, the VAST majority of the followers/fans that you'll get from Facebook are not real accounts. They are dummy accounts. Blackhat (or sleezy tactic) Marketing companies hire people to create dummy Facebook accounts and like pages en masse. Why they do this is a more complicated matter about the nuances of Blackhat Marketing and how it works, but it's a problem for your page. Here's why:

When you post on Facebook, the site's algorithm determines how many of your fans/followers/friends will see your post based on a ton of variables. The more likes and comments and shares your post gets, the more "reach" you get; the algorithm pushes your post to more people based on engagement. The problem with spending money to get more followers is that those followers WILL NOT engage your page. They won't like your posts, or comment, or share.

So it's better to have 100 followers who are more likely to engage with your posts and care about what you're posting about than 10,000 followers that are 99% fake. If you post to 10,000 followers and don't get likes/comments/etc, the 100 people that actually want to see your posts are not likely to ever see them. If you post to 100 followers that care, more of those people are going to engage, and you're more likely to get them to do things to promote your work (subscribing on Tapastic, giving to your Patreon, checking out your website, sharing posts with their friends, etc).

2) Advertise to get more "reach".

This is a little more of a psychological problem. Sure, you can pay Facebook to have your post seen by more of your followers/fans. You can even pay Facebook to have your post seen by your fans' Facebook friends that aren't following you. That sounds like a good thing, at first, but it's not:

It's a scam. The more people pay Facebook as a way to get their friends/fans to actually see their posts, the more Facebook continues to reduce the "reach" of non-paid posts to maximize their profit. By paying to advertise to people who already WANT to see your work and their friends (who are more likely to care about seeing you if your fans share your posts rather than a paid advertisement popping up in their feed), you're supporting a Facebook marketing system that is becoming more corporate and less user-friendly. And if you do advertise a post to non-followers, you'll start getting more of those fake followers that I mentioned above.

Facebook's a useful tool. Get more engagement/likes/followers/shares by writing posts that are calls to action, that give simple and clear instructions for how people that want to support you can do so, easily. Ask your fans questions, get them involved with your brand. That's the way to build an organic following that will actually help you grow. It's nice to have a bunch of fans, seeing a high # is nice, but it's MUCH better to have a smaller, more engaged fanbase ... especially when you're trying to grow.

It's sort of the same here on Tapastic, though to a lesser extent. My comic, Atonement4, hasn't had a spotlight or a staff pick yet, its style is sort of experimental, and so I have a fairly low subscriber count compared to a lot of other comics. But my subscribers and I chat a lot, we're very engaged with each other, I have a great like/comment-to-subscriber ratio, and so I feel like each of my subscribers are super valuable to me. And because it's that sort of organic growth, I'm more engaged with them, too.

Not saying that getting a spotlight/staff pick is a bad thing. It's an awesome thing to have happen to your comic! I don't think that there are any creators here that wouldn't welcome that big boost to readership. But there is something particularly valuable about building a following from the ground up, too.

In short: use Facebook as much as it benefits you to do so, but I'd never pay for their marketing. Hope that helps!

I'd say no. Maybe if you had a gag-a-day comic, but long-form comics won't do well in Facebook's interface. You probably won't make any pay-back from it either except some numbers indicating "Likes", but really, what benefit would that do for you?
Facebook is also the main place where I've had my work stolen and re-posted on more successful pages with a large following already, so.... yeah.... I'd recommend not to.

It took me a while to get into Twitter, but I've had more luck with it than Facebook. I'd highly recommend participating in the weekly chats via #webcomicchat (just look up @webcomicchat and you'll find the information on their page). A lot of us go there to advertise our comics and cover interesting comic-related topics. A good number of my followers on twitter resulted from that, as well as mutual-following between people on Tapastic who just so happen to have a Twitter page aswell). Sharing the comics you read on Tapastic on your twitter also gets you the attention of those who read the comic and the creators which can get you a bit of attention as well.

I'd say actual followers on Twitter come from direct interaction with them (via the chats I mentioned earlier) and people who already are aware of your comic (or your other content, say if you also have a Youtube).

I remember this from another thread regarding facebook ads....
Virtual Bagel:

Yep! This is the best explained reason to not advertise via Facebook.

has anyone had success by posting their comics on Facebook groups?

Any groups you recommend?

I find that groups are mostly preachin' the to choir, but it is because of these groups that I have discovered some awesome indie creations (some on Tapastic, others at smaller publishers). I also like to think that people have discovered my comic through the groups too.

You'll find me here, posting once a week (sharing posts from my comics facebook page)

Webcomics3
Indiecomics2
ComicBookSunday2

We advertise heavily and it does work. We have done some social media (and we do more.), bt Project Wonderful and especially Adsense work well.

The problem with # plan is that the people who follow those are mostly other creators. People keep complaining how "incestuous" webcomics is. When you are only preaching to the choir what can you expect? That being said, I can honestly say I have followed someone because of a convo we had with one of those #, but I have never actually read a comic because someone promoted with those #. I am sure other creators do read them, but it is more to attract other creators than it is to bring in new readers. I think now, with the massive amount of comics out there, and declining readership (even if it isn't declining it's the same amount over 100X the comics) it is important to reach new readers and bring them into webcomics.

Plus you are limiting yourself a lot more on the # promotion because maybe a few thousand people look for them or use them, but a lot more will see your promo on the social media advertising or ad space advertising.

If you are worried one works better do both and see what happens. Then you cover all the bases.
Just my 2 cents.

I don't really recommend Facebook ads, i've had a lot more luck with Project Wonderful. I promote on Facebook groups like Webcomic Underdogs(or the few groups that are actively accepting members) and I rarely ever get a bite from those . Twitter is kind of where it's poppin' where webcomics are concerned, from my experience.

I have had a great experience in facebook ads campaign management1 and that’s why I suggest it to others as well. By using this method our sales had a huge boost and now I will start the FB ad campaign again to promote our other online store as well.

In this competitive work for any business online marketing is distinctive and very crucial for the success. I am also an entrepreneur and have hired the expert facebook ads campaign management team for promotions of my brand in front of the large number of users that are interested in the same set of services that we offer.