Amazon offers the Canon EF-S 10-22mm f/3.5-4.5 USM SLR Camera Lens, model no. 9518A002, for $649.99 with free shipping. That's the lowest total price we could find by $73. This lens is compatible only with the 1.6x crop Canon SLRs; the 50D, 60D, Rebels, etc.

Orders placed by December 21 at 11 pm ET using Amazon Prime are guaranteed to arrive by Christmas. (Non-members need to order today.) Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months. (Note that currently there's a waitlist for Amazon Mom.)