If you can afford $500, I strongly recommend Mary Anna Dennard’s online video series. She walks you through every single step in the process, including how to shoot prescreen videos.
I wouldn’t worry, I am sure that colleges would much rather see a prescreen shot using an cell phone in bedroom with a Wicked poster on a pink wall in the background than an over-produced professional video that is obviously shot in a studio. The content of the video is what is most important, not the format.