if its a good price I would be tempted. A mining card that was taken care of mainly runs the risk of a fan failing rather than a total card failure, which while annoying would not render the card useless, and the odds of this occurring are pretty small.
That being said, its still a used card I would want to see it put through a stress test prior to buying, and have the ability to return it if it didn't work on arrival. Depending on the seller these things may or may not possible.