I may be assuming incorrectly, but it sounds like the existing antenna is cosmetically unacceptable in the test location??? Given that the existing antenna works, can you find a closet shelf with reliable reception?
If you decide you need to buy an antenna, and less expensive is a high priority for you, try a simple rabbit-ears style antenna with no amplifier. These types can sit on most windowsills while oriented properly. You would expect less gain and directionality than a optimally installed RCA ANT751, but it sounds like you have not optimized the mounting orientation of the test antenna so the actual performance difference is hard to estimate.
Example:
https://www.amazon.com/RCA-ANT111E-D.../dp/B000HKGK8Y
(As I mentioned previously, I think Antennas Direct's pricing is justified by the quality of the product and customer service.)