I really recommend looking into a clean needle exchange program, if your community has one. The one here in Southern California has a van that comes to my neighborhood once a week. They have assorted darts and points and even take requests. (I asked them to bring a box or two of 23Gs.)
Last time I went, I picked up 30 23Gs plus a box of 21s for drawing -- all for a five dollar donation. Can't beat the price! AND you're supporting a good cause.
(They also give you a little card to show if a cop finds the darts on you, explaining you got them legally from the program.)