Canon Digital Pocket Cameras

I'm 15 years old (if you wanted to know) and i'm into professional photography now and i want to get a decent camera.
Many have recommended the Canon Digital Rebel XTI so i've started to save up for it (ha ha, i don't have a casual job, i'm only saying up from the $20/wk pocket money). If you could please tell me how much it costs, it would give me an estimate of how much i have to save.
You can recommend a better camera if you want (and how it is better), i just want a camera that can zoom and instantly takes the photo as soon as you hit the capture button (not like the $300 cameras that you have to hold the button down to take the photo).
Thank you in advanced

The camera is relatively cheap $400.00 quality lenses will run you into the thousands.