Failing the acquisition of pallets, cinder/patio blocks and 2x4s work quite well and also tend to be cheap (plus you can get them at Home Despot while you're there asking for pallets!)

Sorry I'm all permacrippled and can't help. )-: I will keep my fingers and toes crossed for your books... my 4,000 or so are in boxes in my basement, with only a thin layer of 2x4s between them and the floor. I've been lucky to not have any flooding (knocks on wood), but I think this summer I'm going to build paperback shelves for the basement to get them up off the floor.