I can't tell from the "readme" page but when you 
use your credit card to buy from AWS, do you pay 
in yen or in dollars? If it's yen, that could 
also save you money in the long run because your 
credit card company will give you best exchange 
rate for that day rather than the fixed charge of 
deputy services. 

Go Sonia go! Post more ^_^

Wendy