Our group bought all our jerseys at once off Taobao, and while I don't know the seller's name, gosh what nice quality! Cosplaying volleyball kids with friends has got to be some of the most fun I've had at cons to date. I have a nice wavy lacefront wig from Wild Hair Emporium on Ebay, which ties up into a bun real easy. I got some legit volleyball shoes and the red/green/white volleyball from Sports Authority, and knee pads from Dick's.
My friends and I have started referring to con Sundays as "Sports Sunday", where we usually bring out comfy sports cosplays to chill on the last day of the con.