if you go to a store, prepare to pay for a lot. If you look on ebay, you can get AAA Ni-mh for about $.80 - $1 per battery. Some of the lots come with chargers too.

The quality of some of those batteries are poor, but my favorite ones come from ebay. I have duracell ones, but they seem to run out pretty fast. If you buy a lot of 24 for $20, even if half of them are really good, you're still better off.