Do yourself a favor, and but "The Piano Book," by Larry Fine.
Plaz is right, get a tech to look at it. Try to find out specifically what was done - complete rebuild, restoration, increments in between.
The last thing you want is to spend $7000 for a piano with a cracked soundboard.
Keep in mind that pianos are like people, they are under a lot of stress, and have a limited lifespan. They don't last forever. The good news is, unlike people, you can replace parts on a piano as they wear out.