If Ты go to a store and [i] Everything [/i] costs $1 shouldn't everything Ты buy add up to $1?

u сказал(-а) EVERYTHING costs $1 so, if u buy EVERYTHING, it should cost $1, shouldn't it?

No... The total cost would be the sum of all the products.

Uh...no. When they say everything costs $1 they mean each individual product costs a dollar, not the total. Plus there's such a thing as tax. I don't quite understand your logic here.

This should (probably won't) answer your question. =P