6 of one, 1/2 a dozen of the other. One man’s “Good condition” is another man’s tired & worn out. It was a private sale, you have no recourse, you should have examined it before buying. Not what you want to hear, but that’s how it is. Caveat Emptor. As previously said, give it a clean, & an airing and either use it or sell it on & recoup some of your money. Hitting the small claims will just cost you more money with little chance of a positive outcome.
Put it down as school fees.