We paid $700 for 560 sf but that was for a screen and re-coat with oil based polyurethane. I think water based might cost more. Did a great job and it's holding up very well.
With all furniture removed by the homeowner, two guys first thoroughly vacuum the floor. They then sand it lightly with a rotary floor machine using an abrasive screen to scuff the existing polyurethane coating. They then vacuum thoroughly again and I think they go over with tack cloth. Then they put down a new coat of polyurethane including matching shoe molding if you have it.
It's a less expensive alternative to completely sanding, staining and coating the floor. It does not correct existing stains or gouges or other imperfections and is only for floors that are already in otherwise good shape.
This sums it up perfectly:
Learn how to screen and recoat your floors so you never have to sand them again. It's the best-kept secret in the hardwood flooring world.
www.peteshardwoodfloors.com