BatterySpace.com has 12 AAAs for $10.50. I generally order a pretty good sized pack of batteries at once so the shipping goes down.

I have used name brand and off brand (Powerizer and such) and have not noticed any difference at all; I suspect they're all made in the same plant in China.

However, I no longer buy any NiMH except for low-self-discharge batteries. They ARE worth the extra money - you can charge them up, let them sit a month, and still use them, whereas normal NiMHs would need topping off first. For AAs I get house brand (Meijer) "precharged" 4 for $7.99. I haven't found any great deals on low self discharge AAAs yet.