Thumb Score: +22

Amazon [amazon.com] has TEKTON High-Torque Black Oxide Blade Nut Driver (8mm) for $3.30.
Shipping is free with Prime or on $35+ orders.

Tekton [tekton.com] has TEKTON 8mm High-Torque Black Oxide Blade Nut Driver (26886) for $3.30. Shipping is free on $25+ orders.

Home Depot [homedepot.com] has TEKTON 8mm High-Torque Black Oxide Blade Nut Driver (26886) for $3.62. Shipping is free