Looks like it has a belt and it might be functioning. I love that cabinet, that's a lovely piece of furniture.
From my experiences thus far: There are no set values for sewing machines. It does vary greatly from one area to another mmmm, you're in Texas, the prices tend to run higher there. Thrift shops are the low end, garage sales/craigslist sorta middle (people ask for high end a lot on craigslist, they don't get it though), eBay/antique malls high end. A complete and actually working machine (not just a claim its working) in a beautiful cabinet will be more expensive then a rusted machine in a water damaged cabinet.