In my 20+ years selling on eBay I have had far more problems with low dollar purchases than higher dollar purchases. People who tend to buy items in the $1-$30 range are often finicky and will work hard to negotiate down every last penny, literally. Buyers in the three figures and up range tend to be more decisive and don't bother to look for excuses to save a few bucks. This isn't true all the time, of course, but this has been my general experience.
Incidentally, this has also been my experience on the boards as well.