I see a lot of people, some not even tech literate, making their own videos on youtube. What's the most popular program for video editing? It doesn't have to be complex, or free.
I wanna upload some songs.

Adobe Premiere Pro. That's a 600-800 professional program used by the industry.

Adobe premiere pro is costly

Well the standard that the industry uses is Avid Xpress. Other notable ones are Adobe Premiere and Apple's Final Cut Pro 2. Of course if you don't have a mac then you can forget about Final Cut Pro 2.

To be fair. YouTubers probably use something along the lines of Windows Movie Maker. It's free. I can't remember what the Mac equivalent is, but I know it's there.

I used adobe premiere pro and the file turned out to be 1.13 gigs for a 13-20mb mp3 file with no video.
I wonder how that happened.

Just used windows movie maker. http://youtube.com/watch?v=qhBkViAPF0I
http://youtube.com/watch?v=yO725ZS7gdg

u can try adobe premiere elements...i used it for work...it's real nice

GIMP does not only edit and create graphics it also has a video editor and animator the GAP (GIMP Animation Package) plug-in and its totally free.

http://www.youtube.com/watch?v=Ti1HZy0F4W8