BikePakUSA via Amazon offers Prime members the BV 8" Frame-Mount Micro Bicycle Pump, model no. BV-GM49L, for $13.98 with free shipping. (Non-members can qualify for free shipping with orders of $35 or more; otherwise, shipping adds $5.58.) That's the lowest price we could find by $4. It features a reversible Presta and Schrader valve and is capable of 120psi of air pressure.

A close price: Ibera via Rakuten sells this pump for $14.99 with free shipping.