Keep an eye out on Craigslist.
I live in AK where everything is a little bit more expensive, and I usually see a few truck tanks like the ones in the link you sent me for $100-$200. Also, it wouldn't take a lot to buy a pump, hose and nozzle, and then have the tank made for you at a local steel place.
I've been watching CL for a good deal for one for my truck that has two tanks. I want something that can hold gasoline (for my truck) and heating fuel (for my house).