I strongly recommend getting all used pianos evaluated before purchasing. It is very discouraging to get a piano—especially a “free” piano which still cost hundreds of dollars to move—only to discover that it is, in fact, not able to be tuned.
If you are interested in looking up the age of your piano, many can be found online at Bluebook of Pianos. All you will need is your serial number and the piano’s make. The serial number is usually visible near the tuning pins (under the lid on an upright).
After evaluating a piano, I can give you a formal document with a monetary value. This is useful if you are selling a piano, or if you need documentation for insurance or tax purposes. I will also determine the value of damage to a piano.