eBay will likely give you your best price if you're willing to ship the bike, the market is pretty skewed right now during winter, although its a great time to work on bikes in my opinion.. but not to many people sell during the winter time cause they think "no ones looking". So if you wanna wait till spring to list it you can probably get more for it then you would now. What could you get? Hard to say.. But on ebay I would guess anywhere between $150-300 ballpark. If you wanna sell locally.. well I bought a bike with complete exage group and quad butted cromoly frame which should be similar to your nishiki locally last october for $60 bucks.. I do live in a smaller town so usually laughter is appropriate if someone tries to sell such a bike for $150-300.