Keltin, I buy the big block at Costco - about 1 1/2 pounds - and it lasts me a few months. It's $10.49 per pound, and is real imported Parmigiano-Reggiano. I think I buy it 2 or 3 times a year. But you can get the 8 oz wedge at Publix in the deli cheese section. I think they carry both BelGoioso & Boars Head brands. I'm not sure what size the can is, but you should be OK with storage for several months.
Many people actually prefer the Kraft cheese. It tastes saltier, but doesn't have quite as much 'bite'. As much fun as it is to take pot-shots at the can, in reality, it's still real cheese (at least the Kraft product is - some of the off brands do use filler - read the label). The big difference is in the aging. The big blocks of Parm from Italy are aged a couple years. The Kraft cheese is aged several months - less than a year. It's during that aging process that Parm-Reg develops its flavor. So the cheese in the green can is pretty much the same ingredients, just much milder.
The other thing that affects the flavor is the size of the grating. The best way to taste the flavor is to slice off a sliver of the cheese. Often, restaurants use something like a potato peeler to makes slivers of cheese for the top of a dish. If you look closely you'll see little white crystals in the cheese, which developed during the aging process. As these explode in your mouth, they release bursts of flavor. The finer the grating, the less of these crystals remain to burst on your tongue. Since cheese in a shaker can is grated almost to a powder, the crystals are pretty much non-existent.
So as much fun as it is to poke fun at the green can, it's still real parmesan cheese. It's just milder in flavor. And because the sharpness isn't so dominant, the saltiness comes forward more. It's really just a degree of flavor & convenience. As with any cheese, people like different degrees of sharpness.
Sometimes, we just like what we're used to. I only buy real maple syrup. I lived in Canada for 7 years, and it was much more readily available & not as expensive. I got used to it. I don't like 'pancake syrup'. But when relatives visited with their kids, and I made french toast, none of the kids would eat it. I had to quickly borrow some pancake syrup from a neighbor.
Try one wedge, and see for yourself which you prefer. Like Mama said, you may find you use both, but for different things. It's all good cooking......
I have learned by trail & error what to buy at WM & what not to buy. The only thing I buy in the fruit/veg area is Bananas . Honeycrisp apples . 
That goes double for the fresh pizza .. I bought one tasteless ham. Then one tasteless turkey.. I think thier meat is way OVER priced I don' t buy it..I bypass the deli & the bakery..
