I have a wiki about Korean Webtoons and the companies that host them. To get information about those, I sign up and read several webcomics. The ones I know of that in English are LINE Webtoons, Tapas, Lezhin, Spottoon, and Tappytoon.
Each of those companies have someway to read their "pro" comics for free. LINE is free to view no matter what. The others have a pay to view system but do have a way to view their pay comics with paying. For Tapas, it's just watching ads on mobile and getting coins and some comics do became free after waiting day to view. Spottoon has a rotation system where comics are free on certain.days. Lezhin does promotions that some comics free to view for a time, give out coins, or some of those comics unlock after a certain amount of time. Note, I never used the Lezhin app so I'm missing there.
Now, Tappytoon, what makes them a bad is that there really isn't a way to view their comics for free or getting coins to buy comics other paying money. According the reviews on the Tappytoon app they used to give out coins through the app like Tapas but stopped for some reason and the users are annoyed by the fact they're forced to pay to view the comics. Granted they have to make some money but that's big turn off. Another thing is that they used to do promos like, you login five days straight and get some coins Now when there's a promo I try to log in but after the third day the promo just stops. Now if it's a bug or something shady going on I don't know.