Found this page which has useful tips on how to purchase a piano. Especially helpful advice when selecting a new instrument for your student:

How to Buy a Piano – wikiHow

Avoid electronic keyboards. These are not the same feel or tone as a real piano. The keys are usually unweighted, the instruments don’t have pedals, and they sound terrible. What you need is a real upright or grand piano. These can be rented or purchased. Renting is not a bad idea for beginners if you are not sure. For my competition students, it is best to have a real grand piano available to practice on daily.

You also will need to identify a good piano tuner. You should have a piano tuner come and service your piano at least once a year, and preferably twice per year.