need battery help
 

hey, i need some help choosing lipo's for my cars. i have been getting together everything i need to start racing and am confused about what batteries to buy. My hobby shop races indoor carpet during the winter and alternates between onroad and offroad when the weather gets nice. Are $120+ batteries what I need? Can I use one battery for the day? Is discharge rate that important? and if so, what is a good rate to race with? Are there brands to stay away from? Are there any "best bang for the buck" batteries out there? My local shop tries to sell me the $125 "race packs" and I don't want to spend $500 on batteries. For what it's worth, these are the cars I have and plan to race; tc5 for RCGT, tc6 for stock touring, traxxas slashes for 2wd and 4wd short course. any help would be greatly appreciated.

ken