Bought new house 9 years ago with tank owned by Osterman. Contact up after 3 years.
From year 3 to 8 I haggled with the them like a fool after they would do an automatic delivery and charge me an insane price per gallon. I had their tank removed and put in my own tank and am paying dramatically less. My point: instead of charging an extra 10% or 20% per gallon for use of their tank (which they had already made their money back on) they were looking for 100%. I would call it greed but I'm not sure it was as it seems to work for them.
So if you have one of their tanks and can't afford to buy your own call around and find another supplier that is willing to supply a tank and work a deal with you. You can only do better!