Home Depot offers the Milwaukee Fastback 5" Flip Pocket Knife, model no. 48-22-1990, for $9.88. Opt for in-store pickup to avoid the $4.49 shipping fee. That's the lowest total price we could find by $3, excluding the below mention. It features a 4" blade, press-and-flip 1-handed opening, reversible wire-form belt clip, and lanyard hole.
A close price: Vandelay-Supply via Amazon offers it for $9.98 with free shipping for Prime members.