We will sell shells to folks that require it if they are attending one of our shoots but we ask that they only purchase what they require for the shoot. We don't want them to "stock up" as doing so (in our case) cheeses off some of our club sponsers that sell ammo in their retail stores.
They understand that as shooters, we look for the best deals and when we buy 100 or so flats at a time, we get a decent price (well used too ...). Any way, we do ask our sponsors if they can meet the price, if not, we buy elsewheer BUT we do not then turn around and sell it all for a profit. It's for our personal use with "some" being sold as required at matches.