Home Depot offers the Defiant Single Cylinder Square Spin-To-Lock Electronic Deadbolt in Satin Nickel for $29.88. Opt for in-store pickup to avoid the $5.99 shipping charge. That's around $25 less than what most sellers charge for this or a similar deadbolt. It includes two keys and fits doors 1-3/8" to 1-3/4" thickness.