*** typed this response thinking it was on my build thread, but since I already wrote it out... ***
Since I work for a salary and enjoy the process, I haven't put too much time into calculating total cost/opportunity cost. However, now I'm curious to see how much I'm effectively paying myself for this work....
I don't know how much time
@LeanMachine put into his, but I know I put in 8-10hr between planning and sewing mine (more so on the planning side). If I make another it will take substantially less time since I now have a pattern and know the best order of operations.
Kifaru currently sells the bag for $230. Since I'm buying my materials in larger quantities (binding and webbing by the roll) so that I have leftovers to do other projects, costs below are slightly lower than doing a one off.
Materials:
< 2 yd 500D Cordura: $16
10 yd webbing: $7
Zippers: $4
Binding: $1
Buckles (including Kifaru K Clips): $20
So, let's call it $50 total. It would be less if you didn't use K Clips, or already had buckles on hand (since you can swap a lot of that hardware between bags). That leaves me with around $18/hr for the first bag, and more for subsequent iterations.