I use the absolute cheapest options available, which is USPS first class. Since I've never shipped anything heavier than a jewel case, and in sturdy padded envelopes, shipping has usually cost about $13-17 if memory serves me right.
As far as shipping time goes, it is inconsistent, but about three weeks to four seems to be about what has happened to me (IIRC I've shipped to Germany and... France, I believe?).
I've only ever done international through folks on forums, so I've never had to deal with ebay/paypal hoops and ladders or buyer return stuff. Luckily nothing has ever been lost in the mail either.