What does it mean by domain and range and how would I use that to fill out the table?

The domain is the set of all allowed x values. In this case, we consider the whole numbers between 0 and 10. So we have x = 0, x = 1, x = 2, ... all the way up to x = 10.
To find the y values, you replace each x with the numbers mentioned and simplify.
For instance, if x = 2, then,
f(x) = 3.50x
f(2) = 3.50*2
f(2) = 7
This tells us that x = 2 packages cost y = 7 dollars.