I have three Honeywell air purifiers, they are awesome for white noise! Got them all off Kijiji for way cheaper than in store, and they keep the dog/cat hair under control in the house too. http://www.amazon.com/Honeywell-Pure...ef=pd_sim_hg_3

I think I only paid $40 each for them. I put one in each bedroom and one in the hallway.