If you're worried about price, you might consider looking at your local Petsmart/Petco/Walmart or mom-and-pop Petstores first. Sometimes they have Halfmoons.
also has Halfmoon Bettas avaliable on their website. $11 for the Betta and overnight shipping might total to be a little cheaper, around $40 or so.
Another option would be locating a breeder on Aquabid that relatively near your area, to avoid the cost of a transhipper.
Try calling some local pet stores first and see if they have any Halfmoons- You might be in luck!