One of the things that drives me mad is when a "cheap" item has a high shipping price.
You know the scenario I'm sure. Item "costs" about 2 euro, but by the time you pay for shipping it's suddenly 30 euro.
If you're using eBay.com from Ireland there's an option to show the estimated shipping cost as part of the display columns. If I can't see a price or it's simply too high I won't bother bidding.
Now there is a difference between "too high" and simply "insane"
Check this out (click to enlarge):
It's obviously a glitch in their system, as the items' listings show a much saner shipping price.
Don't you just love computers?