Where can i buy a good fish eye lens under $50 for my samsung sc-mx20 camcorder?

i just got it for my b-day on the 14th and i noticed that on the lens, it has threads for a lens. and i also read a review online that it can have fish eye lenses. i am wanting to start making more scooter vids now that i have a good camera. on alot of skate and snowboard vids they have fish eye lenses and scooter vids do too so any help because i cant find any websites. please help me. oh and, SCOOTERS ARE NOT GAY!!!