Perhaps consider taking a page out of the pinboard.in playbook: customer #1: $2000 customer #2: $2100 customer #3: $2200 And so on until customers stop sign

Perhaps consider taking a page out of the pinboard.in playbook: customer #1: $2000 customer #2: $2100 customer #3: $2200 And so on until customers stop signing up. Then you start over.