let us take a person who want to do a photography as sideline,
let say his salary is $2000.00, working 44 hours a week, so his is hour salary is $46.00 (round off)
he only has 55 hours free time per week to do moonlighting (minus sleeping time, dinner time, wash up and time for commuting between home and work daily) but most assignments fall on weekends, so he only has 16 hours shooting time the max, the rest of the time spending on post production and admins work.
he spend 10k on gears, computer, monitor calibrating device, software etc to do moonlighting, he plan to recover 10k within 3 years period, so each weekends the cost is $32, and if go by using them 10 hours per week to make money, the cost per hour is $6.50
we take this person able to secure 2 assignments with duration of 3 hours per week, he need to spend two hours for packing gears and commuting, one hour on communication with customers from enquiry till closing, 0.5hr for shoot and burn CD style, 2hrs for simple editing for each assignment.
on this example, he only has 6 hours of chargeable hours, and spending 14.5 hours working on it. his salary and cost for the 14.5 hour is $1094.75, [14.5 hours * ($46.00*1.5)+ $6.50], 1.5 is overtime rate. 14.5hours is consider one assignment is shoot and burn, and the other need some editing.
for this 6 hours assignments, he need to charge not lesser than $1094.75 to make a break even, that is still not adding in any profit yet.