Yeah, they have some measures in place to keep people from easily gaming the market by setting up dummy accounts and so forth.
In any case, I crafted two levels of the badge just by selling dupes and buying the ones I didn't have. I don't spend "real" money on this stuff because come on.
I'm a little annoyed that the items I got out of it each time are worth jack and shit, though. Guess I'll dump them on the market for a couple cents apiece.
One wonders how much real money Valve is making out of the market system. The commish they take is big enough, in scale, that they should be making scads of money, assuming there's enough dimbulbs sinking real cash into it.