I’d have the same difficulty tbh. I don’t live in the US so no rice-a-roni here anyway, but there are a lot of premade foods available here too, and… I just don’t really buy them very often, even if I’m alone, I just cook or throw like a frozen pizza in the oven, but I don’t experiment a lot with those boxed meals. I also only ever buy stuff like laundry detergents at discount so I never even think about the normal price. I go to the store, see a detergent at the regular price, go “fuck no” and buy something else that’s on discount and half the price per liter or per pod. There’s nearly always something available for a good price, sometimes it’s a local brand that’s already cheaper than the foreign brands.

I can, however, tell you the prices of different pasta brands (the cheaper ones, not the expensive ones) to within 20 cents. Usually half a kilo of dry pasta is like 1.19, or under 1 euro on discount. Frozen french fries - used to be around 1.20 for 750 grams, jumped to something like 1.79 and hell I think in some stores it’s 2.19 now unless there’s a discount. Pack of mince meat - depends on size and whether it’s pork, moo or a mixture of both, somewhere between 2.50 and 5 euros per package.