I've seen wheels like this go for anywhere from $1000 to $2000. The 9"s are where the $$ is at. Most 7's go for about $200-300 ea. The 9's, anwhere from $500-750 each. Depending, of course, on demand
(this was of about 2 years ago when i was actively looking... I went with Karma.. found a set as you mention for $1K.) You will likely get offers for the 9s first.