This Portable Bike Pump & Pressure Gauge Set from Wantdo Fashion via Amazon.com drops from $21.99 to $15.39 when you enter the code 7UQZHF5Z at checkout. Other retailers sell this for $27 shipped. Shipping is free when you use a Prime account or free Prime trial. Shipping is also free when you spend $25 or more. Otherwise, it adds $5.99.
Along with the pump and gauge, the set also comes with a mounting bike attachment bracket, six tire patches, two tire pry bars, and a sports needle. Sales tax is charged in most states.