I used 2 x 12" cold cathode tubes over my 7' long 400 gallon tank. For less than 15$ you can get the same setup I used and pickup a dc/ac inverter @ radio shack (or find an old one around your house). It was very durable, low energy usage, cheap and took all of 30 minutes from opening the box to turning them on. Im sure you could also pick these up locally at Frys.
http://www.casecooler.com/ducocalikit1.html