An 85mm 1.4D Nikkor is around $800-900 at KEH. An 85mm 1.8D is in the $300-400 range at KEH. They also list a 105mm f/2.8D Micro for $415. This might work for you at a slightly longer focal length and also give you a macro lens to boot.
Just keep in mind, if you can't move, you may need to use a shorter lens and crop longer range shots in order to cover the whole stage. That is one advantage of a zoom.
KEH does list Sigma and Tamron 70-200 f/2.8 zooms in the $650-750 range. Neither has their version of VR, but they are pretty good lenses.