i have only bought stuff off ebay but it seems to me that some people really charge high prices for postage.
latest example was £3.95 for a tiny item of baby's clothing, and most of the stuff i buy of ebay arrives by 2nd class post.
it seems that most people at least double or triple the cost. in other words, they charge through the nose to claw more money from you. yes, i understand about the schlepp of going to the post office, and cost of packing the goods but in a lot of cases, this seems excessive.