Hey guys!
Can anyone give me a ballpark price of what a mechanic might charge to put a rear wheel bearing in my car?
Just a general price range since I realize other stuff may need replaced as well.

Thanks!

With the proper tools, it can be done on the car, in about 4 hours(per side). So if you figure a little league ballpark figure of $50/hour on labor, that's $200. Just depends on how much your particular shop charges per hour....and if they have the right tools for the job. A hunnert years ago, when I did my first one, it took dang near all day...I dint have the right tools, or the experience.

Thanks Joel!
Im taking it in today to get looked at. I'm thinking a new passenger side bearing as Ive had some play at the 12 o'clock and 6 o'clock position. Anyway, I just wanted to get an idea of what I might be in for. Thanks again!

Play at 12-6 isn't a solid indication of a wheel bearing problem on these cars. A little slop in the stub axle in the diff will give you play at 12-6, so you need to be careful with diagnosing that. Best way to check bearing play is at 3-9, where the stub axle play will not have any influence. 

Oh, ok. Is some play at 12 and 6 somewhat normal then? I took the cat in to have it looked at because I hear a wump, wump, wump (that's my technical term for it) when slow to around 10 mph. Could be a bad tire also. I noticed it after I had new rear tires installed.

Depends on WHERE that play is coming from. Need two people to really check. One to eyeball the stub-shaft(s)/u-joints, and one to wiggle the wheels.
The "womp-womp-womp" is a perfectly legit technical term...I use it all the time, and it usually DOES indicate a bad tire, but a failing wheel bearing can make a similar noise. If you want, you can swap the front/rear tires, and see if the noise goes from the rear to the front.
In the end, you may actually have a bad bearing issue....just trying to make sure that's what it is before spending the $$$, and finding out you still have the same problem. That's never any fun...

Thanks for the help, Joel.
I would have switched the tires but Im running a different size tire up front.
They called me earlier and said that the passenger side bearing is shot. I'm trusting them at this point. They are a good shop but fairly pricy and I know they've got a guy or 2 that work on vettes. 
Price was what I figured after you stated a price.  They want $440 to do the right rear bearing.  I figured i'd add 200 after what i saw you post just because of knowing the place is pricey.

Seeing as this is rear end suspension work, I'm hoping they don't call tomorrow and tell me "what else" they found.

Oh, and another thing...I wish your shop was in PA or I lived in Texas. Either would work for me :)

Rear wheel bearings are a different animal  from the front bearings which are a breeze.  Only a shop with the special tools can do it correctly. A friend with a 78 was recently quoted $800.00 from a shop in Denison Texas. They know their stuff and he is going to go with them. 

Turns out that it was my bearing. They replaced it and had to slightly machine the spindle. Ended up costing me $474. Everything is tight now and no wump, wump, wump.