Twelve percent is kind of high for an amount of data that basically ends up being a picture or two and a block of text. Your average forum does that sort of thing for free.
Also, you have to pay extra on TOP of that if you want to stand out, because eBay throws everything out there in one big pile. You're paying 12% no matter how many eyes actually noticed your listing.
And again... fucking PayPal scrapes up a little more after all that, despite being the same company.
I'm not going to complain too hard about this, since there are at least plausible alternatives for most items (sell games on GAF, sell electronics on Craigslist, sell records on forums and music-specific auction sites, etc.). I'm just pointing out why I avoid eBay whenever possible. I think their service could be more fair than it is.