B&H Photo Video offers the Brenthaven Clicksafe Laptop Lock, model no. 4750, for $14.95 with free shipping. That's the lowest total price we could find by a buck, outside of the mention below. The lock is tamper proof and includes two keys and a 5-foot cable.
A close price: Biddeal_Co. via Amazon has it for $15.29 with free shipping for Prime members.