Walmart offers the Conair Rechargeable Beard and Mustache Trimmer for $12.99. (Amazon has it for about the same with free Prime shipping.) Opt for in-store pickup to dodge the $5.99 shipping charge. That's the lowest price we could find by a buck. It features taper control, two jawline combs, and a 5-position adjustable comb.
Update: It's no longer available for pickup at Walmart; however, Amazon still offers it for $12.99 with free shipping for Prime members.