Just using the brand in question:
https://www.target.com/p/sartori-sarvecchio-parmesan-cheese-...
https://www.wisconsincheesemart.com/products/parmesan-sarvec...
The price is about $7, but you'll notice it's only about 1/3 of a pound, so the per-pound price is $20-21. Which, again, tracks with what I've been saying. The only difference is you might be forced to buy a pound of the real stuff when you get a wedge of Parmigiano Reggiano, so there's a bigger upfront cost, but you'll definitely go through the stuff. It's delicious grated, it's delicious on its own, and it freezes well.