I actually bought about $40 worth of bitcoin a few months ago which is now worth something like $260. I'm wishing I had bought a whole lot more if I'm honest, though I'd probably feel insecure about a larger investment.
About 3 years ago I tried to convince the wife to purchase $500 worth. Not as an investment, if I'm being honest I never really saw it that way, but as a way to support something I believed in. Chances are I would have made a few purchases and let it be. This was when you could buy it for around $17 or so. Would have been a nice little payoff.