Countryboy,
A couple of things to be aware of if you do go the route of buying a used 1100 20 gauge should it be in the back of your mind to outfit it with an additional barrel at some point.
Prior to 1977, lightweight models were made, however, they were built on a 12 gauge receiver, and the newer 20 gauge barrels do not fit on them. The way to tell is try to put a quarter through the barrel lug, if it passes through, it is a 'pre' 77 gun built on a 12 gauge receiver, and almost impossible to find a barrel for. No aftermarket manufacturers produce a barrel for the 'pre' 77 1100 20 gauges either.
If the quarter doesn't pass through the barrel lug, then it is a post 77 gun, and any 20 gauge barrel currently sold by Remington will fit it.
People will tell you that the 'Special Field' model won't accept regular 1100 barrels, and thats not true, a 'Special Field' model will accept any barrel currently produced by Remington. However, a 'Special Field' 870 will NOT, the barrel lug is in a different location on a Special Field 870, and regular 870 barrels will not interchange with the special field model.
Just little tidbits of information I've learned the hard way over the years, LOL.
Good luck in your quest, and good health to you, and Merry Christmas also.