ozone questions! help!!

okay so i got a "ozone generator" off of some guy and it turned out i got ripped off. it wasnt an ozone generator(its not that bad cuz he sold it to me for like 5 bucks) so im llooking into the real thing... how much does a good unit usualy cost?(its only for 1 plant) and what are the side effects because i heard you can get like a constant sore throat from them. and do they make noise? if so are there any noisless ozone generators? and i cant buy them online so where else could i find them besides a hydro shop? would good old home depot have them? thanks guys!