Staples offers the Casio Cash Register (pictured), model no. SE-S700, for $99.99. Coupon code "35961" drops it to $79.99. This $40 mail-in rebate drops it to $39.99. With free shipping, that's $60 off and the lowest total price we could find. It features a 7-position mode lock, eight physical/24 total departments, and four tax rates.
Also available is the Casio Cash Register, model no. SE-S800, for $159.99 before the above coupon code and rebate, $119.99 after. With free shipping, that's $80 off and the lowest total price we could find. It features a pop-up 2-line rear customer display, programmable 4-line logo/post messages, and 25 physical/200 departments. Both deals end October 4.