What is the cheapest Cannon D-SLR that has the capability to record video and audio?

Due to the demands of my chosen course in college, I feel that I must upgrade from a regular digi-cam, to a D-SLR camera. However, I think it's only worth it if I can get my hands on one that allows me to record video (w/ audio), Any ideas on the cheapest one? I don't really need it right away. I can still use my digi-cam, but I can't ignore the quality of photos and videos taken with a D-SLR for too long