Cheaper alternative to parmesan cheese?
Grana padano and pecorino romano are two other very savory, hard grating cheeses that work well on pasta. They taste a bit different than Parmigiano-Reggiano, but are quite good in their own right and often less expensive. You can also look at parmesan type cheeses that are not actually Parmigiano-Reggiano. For example, Whole Foods often has one from Argentina that offers a reasonable price/performance tradeoff. All of that said, in many people's opinion, nothing is really quite as delicious as true Parmigiano-Reggiano.