Let's do the math here. Typically if a small shop opens a Nike account, they're going to start with two styles of shoes. For this example, we'll use GT Blazers and Ishod Dunks. Wholesale costs for Nike are half of what the shoe retails for, therefore the wholesale cost of a pair of GT Blazers is $40, and $47.50 for the Ishod Dunks.
A full size run is usually sizes 8-13, 12.5 not included. If the shop orders one pair of each size, that's 10 pairs of shoes per size run.
GT Blazers: 10 pairs x $40 per pair = $400
Ishod Dunks: 10 pairs x $47.50 per pair = $475.
I don't know if shops pay shipping costs for that stuff or if the company eats them. But there's your cost on the shoes.