Amazon offers Prime members the Iron Gym Upper Body Workout Chin Up Bar
with free shipping
. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $10.30.) That's the lowest total price we could find by $13, outside the price below. It uses leverage to hold against the doorway, eliminating the need for screws or other hardware;
A close price: DealsofNow via eBay
offers it for $24.97 with free shipping.
: As a reader found, FreeShipMounts via Amazon
offers a similar item for $19.99 with free shipping.