I recently listed an item on eBay & was pleasantly surprised that there was no listing fee (up to a limit of 5 a month, or somesuch). I didn't see the fine print, though (if there was any).
I found that when the item sold & I was charged an 8.75% Final Value Fee ($7.53 on an $86 item), where I was expecting a sliding-value fee of $4.33. OK, so it's only $3.20, but I felt screwed.
The good news is that when I wrote them about it, they credited me the difference.
I'll bet that a lot of sellers don't even notice the higher fee.
You gotta watch those bastards, Bob