We've just been to GC, it was very nice! Took a bus to the public beach, which is right next to Calico Jack's, where we got two lounge chairs and an umbrella for $20 (they also had some less nice ones for 15), which we thought was reasonable. We were going to have lunch there but ended up getting food from nearby where some locals had set up - food was good and plentiful for $10 a plate. Got a bucket of local beers from Calico Jack's - I think it was 5 beers for $20, again very reasonable.
We took a shuttle back from there to the port, which was $5 per person, if I remember correctly - I'm sure we could have taken a bus back, too, but this just seemed easier.
Overall, we loved it there! It's a beautiful beach, and the entire place seems clean and more civilized than a lot of the other islands