(1) at first I was angry when I read your post; the guy should have known $1 was not enough. He is a wiseguy. But better to pay it rather than risk negative feedback. (You could nicely ask for additional money, but it may not pay if you have a non-personal PayPal account., and they charge you a 30 cent minimum for receiving payments.)

(2) I have something about extra for non-US shipments in my auction boilerplate. See this auction of mine, for example:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2118903869

(3) Don't find the rates at the post office. Save a trip and look online:
http://ircalc.usps.gov/

Robert