I prefer small, these big stores like the ones you mention can only sell so cheap because they buy such large quantities. The vendors that sell them contracts don't want to turn away business. I worked for this one warehouse and their biggest contract was a super store which they had no choice but to offer the lowest prices for them because they made up half of the companies profits. Businesses don't turn away those types of clients, so they will sell super cheap, which mean the giant stores can also sell cheap and still take home healthy profits. Unethical, and unfair monopolies, so I prefer the small stores who will offer quality at a premium price but not too premium.