Buying a Balloon printable sheet

Lola bought a balloon at the circus. She paid for it using six coins.

How much might the balloon have cost?

What is the largest amount Lola could have paid?
What is the smallest amount Lola could have paid?

Imagine that Lola has two different types of coin.
How much might the balloon cost now?
Can you find all the possible prices? How do you know you have found them all?

Which of your answers seems a reasonable amount to pay for a balloon?