I'm considering picking up a used Canon 10D for the school photo club. Saves some money up front, but what does it cost to replace the shutter if it wears out? Canon won't provide estimates unless I provide a serial number -but I haven't bought a camera yet. I could ask using my 20D serial number, but I've also read where after sending in the camera, Canon asked 3x the value of the Camera for a shutter repair. Any one have experience with the cost of a 10D or 20D shutter repair?