Well, Here we go

If you are really squeezing the budget, as Naturist said a small solar will go a long way both to power and to education, that Solar Blvd site also has a 100 watt kit for roof mounting for $150, and it has a 20 Amp controller so you could add a second panel later. Personally I worry about the portable being stolen, and with roof mount, it's always working, even when you are moving.

If it cuts your genny time in half, gas savings will pay for it fairly quick. And when you add the inverter, no noise at night.