I'm looking for a good place to buy Halloween costumes for plus sizes?

Hi. I live in St.Augustine, FL. I'm looking for a place where I can buy plus sized costumes for Halloween. I looked online, but I am Leary of ordering online as most sites will not accept returns, in case it doesn't fit correctly. I can travel to Jacksonville, FL and I will be in Orlando, FL next week. Does anyone know of any great costume stores in any of these areas? Thanks so much! ( I'm usually a size 14 in all my clothes, but so many costumes are not true to size and they tend to run much smaller)