I want to start sort of a project site for my class where we can upload and download our projects (share) the files would be relatively small say 300kb each... is that allowed here?
If the files are relatively small then there is no problem. But if you mean to use x10Hosting as a file server, it is not allowed. Instead a better option would be to use FileVIP, x10's file hosting server.
Using fileVIP would be a better idea either way, whether the files are small or not, it's probably alot more faster to have them hosted on a fileserver rather then on your website.