Walmart offers the Allen Sports Deluxe 2-Bike Spare Tire Mounted Rack for $29. Opt for in-store pickup to avoid the $5.99 shipping charge and drop the price to $27.78. (Amazon has it for the same with free shipping for Prime members.) That's the lowest price we could find by $69. It mounts on a wide range of externally mounted spare tires and features 15" arms, individual cradles with tie-downs, and a lower frame.