OldFingers57: "I got mine off ebay. The 8 gal ones are fairly easy to find on there. I got mine about 5 yrs back or so for about $40. "
Be careful buying them off ebay. I got one and ran water over it with a hose to test it's odor/water "proofness". It leaked like a sieve. Of course I'm sure a new gasket (it had a gasket that had taken a set) would help or fix the issue, but be prepared to put in additional effort/expense if you don't want it to leak (or smell).