You have a few options that aren't hard on the wallet.

You could buy a simple coffee grinder. Around $10 at Wal-Mart or any major retail store. I find they have pros and cons though myself. For small amounts of weed, I find it pulverizes the shit out of it. That's good for grinding up large amounts of hash making or whatever, but for bowls and joints. I find it an overkill.

I have a Sharpstone grinder w/kif catcher. It was about $25, but it was a good investment. I get a bit of kif here and there and it easily grinds the herb up nicely.