I had a 1000 gal underground tank installed 8 years ago. No money left in the budget to pay for it, so I went with one of the local companies that I somewhat trusted and they installed their tank in my hole. It would have been $2K to purchase my own.
If you figure I have been using ~800 gals per year and that I am being overcharged $0.10 per gallon, that comes out to about $640 dollars that I have paid on my tank. I think I am coming out ahead.
Plus the propane company has been out twice to fix problems with the tank (free). Remember, too that it will be thier problem someday when the tank needs to be replaced.
Based on other people I have talked to locally, my propane price is pretty fair also.
I rent my tank and I am happy with it.