Replacing Tow vehicle, clueless :P

If you're not towing often or out west I think a gas truck would work, and you can definitely get more for your money with a used gas truck because they depreciate a lot faster. Another way to save is to target less popular configurations such as a super cab versus a crew cab. I wouldn't worry about the 2500/3500 distinction since they're generally the same truck outside of a lighter rear spring pack, and that can be addressed with bags or timbrens - no reason to limit your options. Just make sure the tires are up to snuff with what you're wanting to haul. If you can find a six speed over a four speed transmission within your budget that would help the gas engine out a lot.