Clown Adult Costume You’ll feel right at home making jokes, balloon animals, and goofing around at the fair! Costume Includes: Hat and jumpsuit with neck ruffles. Available size: One size fits most adult Standard. Clown costumes are fairly popular so you should be able to find them pretty easily year ëround. Check online and in the classifieds. Also, call costume shops and ask if they have costumes for sale or rent. You can also borrow clown costumes form those who’ve purchased them before. Also, your local theater company may have clown costumes they’d be willing to let you borrow or rent.