What are some cool international programs?

Im looking for something similar to an exchange student type thing i suppose, im 16 almost 17 and i love to travel, ive looked into programs like iyac, and national geographic student expiditions, and like adventurescross countryprogram trips, but i just cant seem to fiind anything that is either not overly expensive or for a super long time periord.. help!? any ideas or know of anything u went on.. thank you!