ive never really got why you would list a cage for sale without having the dimensions listed... sure you see about how big it is but not really... since just 4 inches either way of what you think the cage is kinda either make it quite alot better or make it kind of too small...
The main thing to worry about with a cage for a small to medium size bird is the bar spacing. 1/2" for smaller birds and up to 5/8" for a GCC size bird.
I got my cage off Craigslist and couldn't be happier. It was the exact cage I was looking for, and got it for $175. My GCC LOVES all the room, and I like the storage underneath.