I got a prescription from my doctor and they had a location I could go to... Mines was covered by my insurance...
I bought 3 from target and 2 from the motherhood maternity store. My target ones have lasted alot longer & seem to be a better quality.
Most physio dept in your hospital give them out for free if u attend their pelvic girdle pain classes.but thats in ireland.no harm in enquiring wherever u live though.