As a person who has cosplayed as Ness (all these little kids who played SSBB thought I was actually Ness because I already naturally look like him to begin with and signed some autographs)i know the requirements to earthbound protagonist clothes.
Converse all-stars are the best for shoes, I suggest getting red ones, and painting the white parts yellow.
for the hair i suggest getting an Elvis Presley wig similar to this
http://img.costumecraze.com/images/vendors/pony/19080-large.jpg , dye it dirty blond and gel (or some sticky substance)it so it has a spiky top instead of a rounded top
I got my jean shorts from Value Village, though if you want to get new ones, Denim is the ones you want, which can be found just about anywhere with clothes.
good luck.