The best way to save money on batteries is to use the same kind in every application. I use only A123's. RX, ignition, accessories, etc. AND, I buy them only from vendors that guarantee them to be first quality, genuine batteries, sourced only from A123. Radical RC, Electrodynam, and NoBS are the ones that I know for sure offer the real deal. One type of battery, one type of charger, one type of connectors, interchangeability between planes, long life and NO FIRES!!! That's a peace of mind that's hard to find in our hobby.