I recently sold a bunch of books on ebay for seriously low prices, like 50 cents and a dollar. I dutifully sent them out book rate, on time. One person bought a book for a dollar and has sent me no less than 6 emails about the book and why it hasn't arrived yet. Uh... because when I'm selling crap for a buck, I ship the slowest cheapest way.

I don't mind taking a huge loss on books, I'm really selling them to make room for more books, but I do mind being harrassed over a $1.00 item.