We use heat pump for primary heating/cooling (but try to keep it from turning on via burning wood), wood stove 24/7 once it gets cold, and still burn 200 gallon of propane through the propane logs each Winter.
Two fills on the 100 gallon tank per Winter usually, but I am locked in at a little cheaper price.
Like said before, fill in the off Season and you usually get a much better rate.
Also with a tank your size, make sure you are not set up on the plan where they come fill it automatically quarterly, monthly, or whatever. A nice convenience but you will run into small charges/hazmat fees etc for a partial fill up each time. I'd rather just keep an eye on the guage and call them when needed than pay a $12 fee to fill a small amount each time.