As a user, I want to define a minimum and maximum price that applies to each transaction.

Example: if I have a billable for bank transfers (sum aggregation based on the amount), I want to be able to apply a 2% rate on each transfer, with a minimum of $1 and maximum of $5.

For a transfer of $50, the fee should be $0.50 but the minimum applies, so the final fee is $1.

For a transfer of $800, the fee should be $8 but the maximum applies, so the final fee is $5.