What is the purpose ?
for the new learners ?
Besides, for used piano, you can consider N手 as well.
a 20~30 years old upright one may be on sale for around $3K.
of course values varies a lot for different brands.
Here the website of pianoworks in Duluth, GA --- http://www.pianoworks.com/
It has Brand New & Pre-Owned (used) Pianos.
You may interested in Steinway & Yamaha.
Tips:
1. Steinway -- the Mercedes-Benz in piano industry;
2. Yamaha -- the Toyota/Hona in piano industry;
3. for beginners, you may consider buying a upright Yamaha because it's much more cost-effective;
4. for mid-expert level palyers, you 'd better buying a grand Steinway because it's much more performance-effective;
5. you may ask a piano expert to have a final check for you.
I bought a year 1979 upright Yamaha (19") in pianoworks 10 years ago for about $2500. It's been performing well since.
hope this will help.
Pay attention to estate sales. I helped someone to get an excellent Kawai baby grand for $3500. of course, you may need to have patience to find the right one. here is the web site: http://www.estatesales.net/estate-sales/GA/Atlanta.aspx.
if you find one for sale, call them first to schedule a preview since good pianos at good price sales fast. good luck