Replying to Vegas 5- huge files.

so ive been editing with vegas 5 for a little while now, but ive noticed the files are HUGE after i render them. its only a 1 min long video, not alot of effects and a song, off a shitty mini dv camera. i put it in .avi at 720 x 460 (?) and it was 288,000 ish kb. i just found out how to change the resolution and i had it at 360 x 240 and it was still 281 kb. anyone know how to make it a smaller file without completely destrying the quality? it was so big it wouldnt even upload to youtube.