Trade me your currency!
So I don't necessarily like to collect things for rarity or worth, I like things that look cool. One thing I think look cool are coins and dollars. Would anyone from a country other than the USA be interested in either trading or selling me some of your money?
Depending on what the exchange rates are would give me the amount I'd be OK with spending. I'm hoping to keep it around $20USD, but that might fluctuate depend on shipping and how cool your money looks.
I've checked different banks online and most charge over 8 bucks in shipping our have a minimum of a few hundred dollars.
*edit - actually read the rules and realized this should be in the pub