Duracell Procells are the only way to go.
AA's for Halo last ages in practise / walkon but still change for every tourney.
very cheap if you can find someone that can get them.
Anybody you know a teacher or work in local government, thats your best bet.
My Normal Order
10 9 volts and 20 AA's costs £17.33 inc. VAT.
Expensive though, as people on my team never have any Fcuking 9 volts!!!!
Laterz
Ian