Largely depends on condition. Unfortunately, the GC3 is not as sought after as the 1 and 2 and there are some who even prefer the 4 over the 3. the 3 is generally more sought after than the 5 or 6 though. the GC3 is much more common than the 1 or 2 for what its worth. i have a pool room near me with 20 or so GC3s!
In mint condition you can get ~3k+ and in ok condition expect $1-2k. I saw a pretty well loved one for sale used at a showroom for $4k and I think it sold pretty fast but that also included delivery and installation with new cloth.
someone who knows more feel free to correct me