Decent quality CFL's (I'm NOT talking about Walmart specials) will set you back $8-10 a piece. So you've got enough for 4-5 bulbs, assuming you don't also need fixtures to put them in. Thats's enough for one or two plants.

You can probably get them cheaper on line. But definitely go for the better quality lights. I bought a bunch of cheap bulbs on my first grow and ended up replacing several of them within a few weeks because they quit working.