Locking in propane gas prices now??

[all4money]

We've been in our house a year now and we just got a letter from the propane company that offers us a chance to lock in a price of $2.20 per gallon now (to be effective Sept 4 - Mar 31).... OR option 2 is to PRE-pay for at least 200 gallons now at $2.00 per gallon. I could do neither and just pay as needed this winter but that is the gamble in case prices increase. What do you guys think?

Option 1: lock in a price of $2.20, payable when tank is filled this winter
Option 2: pre-pay at $2.00 now, tank will be filled this winter for the preset amount when needed
Option 3: do nothing and just pay whatever the market says this winter.

Last winter we filled up the tank at $2.00 per gallon for 450 gallons totalling over $960 with taxes included. Propane is our only source of heat in the house so I'm sure we'll need a fill up before the winter is over...

[myself]

We keep the heat higher than most folks.
Our last rate was $1.93/gallon and that wasn't prepaid.
We could have locked in about 6 months ago, when the rate was $1.82/gallon.
We also go through a lot of propane (heat/hot water), about 350 gallons/month average during the winter.