I thought it was time to step up the segmented work, so I got a Powermatic 20" disc sander. After searching around, I have found prices from $8.75 to almost $20 per sheet for 20" PSA sandpaper with minimums from 2 pieces to 25 pieces. Does anyone have a source that they use for the sandpaper so that I have an idea of what quality paper should really cost? Thanks!