Calculate value when checklist option is checked

Hi there,

I have created a consumer admin interface, which has checklists which can be checked/unchecked.

I want to assign a value to each checklist option, and then have a box which shows the total value of the combined checked boxes.

e.g. Checklist 1 = £10
Checklist 2 = £15
Checklist 3 = £20

When only checklist 2 is checked, I want the box to show the total cost to be £15.
If all three boxes are checked, the value would be £45.

Could anybody help? Really appreciate it.

Al