Grab a cheapo laptop PSU (with a standard plug), should be around $19.99-24.99+tax depending on where you get it from. Personally I grabbed myself the Turnigy T20Pro, but it's definitely overkill for this application (if I had like a 4 bank charger and needed to charge 4 batteries at once it should do the trick if I don't charge all the batteries at too high of a current). It supplies like 16 Amperes at 14 Volts and the single bank charger IIRC only needs like 5 Amperes.
Just make sure the PSU you get outputs 11-18V or you'll run into problems.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE