Don't buy used cat items

A few weeks ago I bought a nice used cat tree for my strictly indoor cats. Because my cats never go outdoors, they have never had fleas. I should have known when the seller said that her cat was indoor/outdoor that there would be the possibility of the cat tree being infested with fleas. Now all the money, and more, that I thought I saved by buying a used cat tree will be spent defleaing my cats and, possibly, my whole house.
So, I hope my mistake will keep someone else from making this same error. And if you have indoor/outdoor cats, I have a nice cat tree you might like. And to the person who sold the item to me, would you be interested in buying it back?