I use Etsy, and I haven’t had too much of a problem, but I hardly make any sales so idk if I just haven’t had enough to see the problem
But, I had a recent sale the other day. Here’s how the fees broke down—
Sale totaled $71.14, which includes the sales tax paid for by the buyer, and the shipping fee. Besides tax and shipping, payment was $66.72, but Etsy fees took $7.72, leaving me with a net profit of $55.28.
Now, one complaint about Etsy is the offsite ads. You’re automatically enrolled in them, and if you make a sale from an offsite ad Etsy takes 15% of the sale for “advertising fees”. You can opt out of offsite ads though, thankfully!
Etsy lets you buy your shipping labels, which you calculate from the size and weight of the item when packaged. The buyer pays for the shipping, and you pay for the shipping label from Etsy, which is a heck of a lot cheaper than paying at the counter at UPS or whatever.
I don’t know about the other sites, but that’s the personal experience I can give you about Etsy. Hope it helps!