Check with a Schwinn dealer. I asked exactly the same question about my 20 year old Schwinn Traveller, hoping it was worth something.
Initially, I was disappointed. I was told it wasn't really worth anything at all (not a collector's item). So I resigned myself to riding it around for a while.
To my suprise, I found out it was worth several times what I paid for it, but not to any collector; I had rediscovered my own love for cycling. This made my old
Traveller 10 speed priceless.
Now, of course, I have a much newer, lighter bike, more appropriate for my purposes. But I would not have this bike were it not for my faithful Schwinn. (I eventually gave the Schwinn to a friend who wanted to start riding, but could not afford a bike).