Start by encouraging everyone you know to open a wallet and send them a small amount as a gift.
Whatever amount you can afford to lose....
If times come when bitcoin realy booms, even 1 bitcoin will become something worth having.
Think of it this way, 21 milion ppl can have 1 btc, 2,1 milion can have 10 btc, and since there are cca. 12 milion milionares (in USD) in the world, that means that 1 bitcoin could be worth 1 mans retirement.
I have 3 btc, sadly cant afford to risk more, and i think of it as a great investment, and if it fails somehow, well atleast i can say that i tried.