They dont sell goods at cost 99% of the time. DECA uses a cost+ model and loss leaders to compete with external price pressures ( e.g. Milk). There is some good discussion on the cross posted link about the commissary, px and military living

And at Navy and Marine bases, you can find a NEX (Navy Exchange) which is just a big department store that sells all the major brands. They even have video games and toys.

More perfect union just did a video on this

Don't spread awareness about this. It'll get picked up by vaccum brained twitter bots, and before you know it politicans and influencers will be frothing at the mouth to cancel it.