To give you an idea.
Let's look at a 350Z or a Pontiac Solstice/Sky for comparison.
The Nissan 350Z having a N/A V6 would probably be the closest to compare to a V6 Camaro. They both have around the same HP too.
According to turbokits.com
http://www.turbokits.com/350Z_turbo_kits.html
There are four turbo kits available for the 350Z...
Two single turbo kits for $4795 & $4895
Two twin turbo kits for $6895 & $8895
Now, if you don't have the know how and don't install it yourself it's also going to cost you labor to get done professionally.
You'll also need supporting mods such as...
Transmission = upgrade clutch and/or flywheel
Electronics = boost controller, turbo timer, etc
you may also have to upgrade axles, possibly suspension...
And for running high boost applications you probably would have to upgrade the internals, either by getting a re-inforced block, cams, pistons, etc.... Those aren't cheap either...
Oh and you'll have to tune it as well.
So there's more than you think.