Here is the way to make some money:
order 1500 bellcranks at a time
$1000.00 of wood at a time
Buy large bundles of cardboard and cut your own boxes
Make the best kit that you can and sell it for as little as you can
Get good workers who donate part of their pay to helping kids get the models
order 3000 screws at a time
order 20 sheets of plastic for windshields
Invest in a good laser printer
and lastly ... count every penny.

I forgot, one more thing; treat your customers like family. 3 times a week almost every week I get request for free items: "I am building a scratch model and I need a bellcrank, can you send me one" or a cowling, lead-out wires, eyelets or wheels. We try to fill all of the request and even give away control handles and line when it is needed.
Larry