A few suggestions to assist your shopping:

Purchasing a New Piano:

1) Buy from an authorized dealer of pianos.  As you would buy a new Chevrolet from a Chevrolet dealer, deal the same way with pianos.

2) Everyone has opinions on sound and performance, thus technicians will have differing opinions on new pianos.  Ask around, ask your tuner, ask teachers what they favour.  Technicians can also advise on how easy a particular instrument is to service, and what problems you may encounter with each.  Ask an independent technician, or more than one, for their opinions.

3) Don’t be in a hurry to purchase.  Go back to each dealer and ask more questions.
Purchasing a Used Piano

Purchasing a used piano is much more of a challenge. “Buyer Beware” A piano technician should always inspect a used piano before purchase.

Check out the Piano Technician Guild’s website for some good advice.

Another well-written article here, “ten things to do before starting your child in piano lessons”

Independent technicians are more than willing to offer advice on potential purchases

Be prepared to see a number of pianos before making a final decision.

For more on this subject, read this pertinent article http://www.pianolifesaver.com/english/blog/spec_blindness_and_how_to_avoid_it

We do not recommend “grey market” pianos.  These are used name-brand Japanese pianos, imported from Japan often from music schools and conservatories and sold in bulk across North America.  Authorized dealers of these names will not sell grey market pianos.  As an example, if you are considering a Yamaha, their recent pianos intended for our market have a notice stating that they are “specially seasoned by the manufacturer for sale in North America” – see the photo at the bottom of this page.  Since most of these instruments are past their factory warranty period you may have difficulty with service issues should the piano develop a serious problem.  Our experience with this type of instrument is unsatisfactory. For more information see this FAQ.

Buying privately is likely a better deal than from a store, or from a hobbyist who does business from their garage.  The exception to this is purchasing from an authorized name-brand dealer who may have trade-in pianos.