I get mine off ebay from onlybatteries.com. I use 2000mah nimh in both RX packs and in my TX. Typically I'll be able to go weeks without having to recharge the TX (but i haven't had many chances to run lately). They do last WAY longer than alkalines.

Picked up 24 of these AA's for $24.99 with $8.95 shipping. Of course that was a while back but you should be able to find a similar deal.

Enjoymentboy