I invest in foreign currency and spend it when I need to. What I do is purchase it over
ebay or Craig's List (or whoever is selling it or wherever it's being sold). I wait to see how the exchange rates do. I read before I invest. I'm finding the South American currencies are becoming most profitable. When I think it's time to get out I either spend the currencies (to anyone willing to accept them in trade) or I auction them off.
If you're looking to purchase any particular currencies let me know. I have a lot, even less common ones. I sell on
Overstock Auctions and have done 1000 trades there so I'm reliable.