I'm not sure you'll get much for that budget to be honest.
However have a look for a sigma 24mm f2.8 'superwide' - sufficient optically with fairly pedestrian focus speed, best of all is that they are often cheap on the 'bay. You will have to confirm that they will work with your digital EOS though as I have read that some do not. I had a Nikon mount version and tha worked just fine.