I miss being in the Midwest, could find all kinds of good little deals like this. I now live in the land of coal and gas/oil, everything's jacked up just because a percentage of the population is union and therefore gets nice wages.
Back when I had to tow a UHaul to move out here, I first looked at Walmart. Anyone else who's been there knows the prices they charge on the kits.
I instead went to a store called Theisen's - hardware/farm supply store located in the Midwest, I'm not sure how many branches they have but I can confirm locations in Dubuque, IA and Maquoketa, IA so anyone near the IA border in Wisconsin or Illinois doesn't have far to go. I got a basic set (hitch, ball, pin and seven-to-four wiring adapter) for I believe around $20-25. Theisen's isn't the cheapest on a bunch of other stuff, but trailer hitches is confirmed. As a bonus, if you ever need chain, miscellaneous bolts and whatnot, they sell all that by the pound as is the norm.
I guess bigger Walmarts may carry more selection, but anything not "Supercenter" usually just has the Reese kits, running $30+ not including the harness.