Cloting
Third, get one that is not too costly like a new model. The price should be a top consideration. The price of the used device should be less than the new model since that is the sole reason you would purchase a used one in the first place.
Fourth, look for one that has cheap replacement parts. In case some parts will not work, you will not be spending too much on them. If you get a used snow blowing machine and yet its parts are very expensive to replace, you will find yourself in anguish when you see the high costs of replacement.