Lefty, a lot depends on the park and what they charge for electricity and what you have to pay for propane. Where we were in Texas and Virginia, electricity was cheaper than propane. Here in Washington, before propane went down, electricity was a good bit cheaper, now it's about the same-maybe propane is a little cheaper. Propane is $2.40 a gallon so it cost about $21.00 to fill my 40# cylinder and I'm using about 2 a month and about $80 in electricity. Fortunately, I don't have to pay for either as a work camper.