Pacific Airwave Mark IV's should fall a bit below that price range now. A PacAir Pulse ought to be right in that neighborhood too. These were great gliders to learn on. The Wills Wing Spectrum was also a double surface beginner glider. Both of those were quite popular in the US.
For HG in the US, start with
www.ushga.org. Since you didn't mention your location, I've just given you a bit of info pertinent to the area I'm familiar with. It may be useless to you, but hope it helps.