I'm used to pay more for shipping than the actual article price. I always keep a record of what I pay for shipping, and don't mind if the seller charges 2-4 bucks, as I've been a seller and understand that boxes, packing time, gas and time to the Post office cost money. Many times, it's simply that seller's have never sold outside US and doesn't now how to get the right quote. When i feel they are charging more than actual postage I politely ask wether they can double check, or suggest the right shipping option. Sometimes I ask for a refund if find that the seller charged a lot. For example, I paid a seller for airmail and he sent the goods surface mail. He saved 25 bucks, so I asked for a refund and he gave me. The other day I received my worst eBay purchase ever, a set of CB350 carbs, whose seller said "chrome looks good". I bid 55 bucks and she said postage was 50. I told her if that was the case I didn't want it so she can leave me negative feedback on the spot. She told me she would double check, and also suggested that the chrome was "not that good". Finally I paid 30 bucks for shipping. She didn't fill out the custom form, so I had to go to the custom office in the airport and pay duties, to discover a piece of crap, with pitted chrome covers, float out of the assembly, with dings and bends, rusted float needle, broken diaphragm... I told her, and she got pissed off and told me I was to blame for bidding on item when she was not willing to sell abroad!!!! WTF!!! If I win the auction and you agree to sell, I deserve the same right than anybody else!! You simply lied on the item description!!!
I never ask for shipping beforehand because I have discovered that many times they give you a quote, and if you win, you are agreeing to pay that, so if they charge you 10 bucks more you can't complain. On the contrary, if you complain when you receive the article, many honest sellers will send you a refund. It's important to know more or less how much shipping can be.
Raul