my pre 1900s singer sewing machine

Me and my husband were going to town when we saw a yard sell. We stopped and saw this sewing machine. We asked the man about it but all he could say was that the old lady that had owned it had past away and she had said before she died that she had had it since she was young. I thought it was a really cool piece and he only wanted $40 dollars for it. So we bought it. now i bought it on a wim because we dont know anything about old sewing machines. i was wondering if you knew any more info about it, like how much it would be worth. Now a friend of mine went to the singer website and looked up the serial number and it came back as coming out in 1892. the machine still works and turns freely as does the base, where the petal and wheel is at the bottom. the only thing missing that we can tell is the belt that attaches the two wheels, but other than that there is not much we know about it.