Amazon has the Kidde AccessPoint Push Button Combination 2-Key Lock Box (titanium gray) on sale for $8 + Free Shipping w/ Prime. For non-Prime members shipping is $5.99 or free on orders $35+.
Also available:
Walmart has the Kidde AccessPoint Push Button Combination 2-Key Lock Box (titanium gray) on sale for $8 + Free Store Pickup. Alternatively, shipping is free on orders $35+.