A best bet is the Swann Black and White Video Doorphone (pictured), model no. SW244-BVD, for $79.99 before the above coupon, $69.99 after. Opt for free Ship-to-Store pickup to avoid the $6.99 shipping charge. With pickup, that's the lowest total price we could find by $15. It features a 4" LCD screen and two-way audio communication.
Of note, in-store shoppers can get the same discount via this printable coupon.