Looks like a Miyata, but not a Koga Miyata. It also looks to me to be near the lowest of the Miyata line for whatever year it is. IMO, if someone offered $50 I would take it. Perhaps someone would pay more, but finding that person might take some time. Keep whatever you want to use on your new bike, like the fenders, baskets, and rack if you want it.
This should actually be posted in the appraisals forum though.