Our dealers rent tanks for about $8 per month. Catch is no other dealer will fill the competitors rented tanks. You are in effect held hostage to whatever price dealer wants to charge.
Dealer I chose was poor about keeping my tank filled. I was supposed to be on a regular route so I never run out. I ran out on a Friday evening after closing.
Couldn't get ahold of my dealer so called another guy and ended up buying a new tank. This was in 2000 and I spent about $800. I now keep track of my own propane level and shop around for best price.