Dreams.

I had a dream that in NationStates, you could get random chemical elements in their pure form delivered to your email by subscribing (for 2499 rubles, for some reason). They send a small amount, but with a good chance of sending something expensive, so I collected a collection of rare earth elements in the form of powders (although I'm looking at it now, and I think I overestimated their value in my dream).
And then I even got cesium, which is great, where else would I get that...