It costs $1 to 'unlock' and $0.15/minute after that. So a $5 payment requires: 1 unlock $1 and $4.00@0.15/min = 26.7 minutes of "usage" (note, not ride, usage, the 0.15 is paid per minute that a user has the scooter "unlocked") before the $5 "finders fee" is repaid by one scooter and one rider.
The numbers shift of course if the same scooter is "unlocked" by plural individuals during the day, due to the $1 unlock fee. Five usages of a few minutes each for a single scooter in a single day repays the $5 "finders fee" just with the $1 unlock fees alone.