Hi Shannon,
You can find most everything you need to know about the bike in this link;
http://www.trfindley.com/flschwinn_1981_1990/1981_12.html
As far value, there are several variable determinants that you need to consider. The following is my own list. Others might not necessarily agree but are welcome to contribute.
In order of importance:
1. condition of the bike.
2. the time of year the bike is for sale. Spring is best for sellers.
3. the location (city) of your bike.
4. the female version is usually a minus because guy's bikes are usually ridden hard and torn up, making them more rare.
5. the number of bikes made, Schwinn is/was a mass producer - not so rare.
6. the model of the bike. Low-dollar models of Schwinn, such as the World Sport are not highly sought after compared to other high-dollar models. The Schwinn catalog PRICE PAGE will show you the ranking.
http://www.trfindley.com/flschwinn_1981_1990/1981_32.html
Also VERY important is whether it was made in Chicago or not. The head-tube badge usually provides a clue.
With all the above variable factors in mind, my own wild guess would be the in the range of $40 to $150 without knowing all the details.
Steve