I have a TOPPS 250 Nolan Ryan card and wamt to know the value...

Please see the following link:

https://www.askmehelpdesk.com/collectibles/baseball-cards-125212.html

In order for someone to really come up with a possible value for your card, they would need to see it in person. The condition of the card makes a big difference as far as the monetary value of the card. Baseball card collectors get really picky about the conditions of the cards.