I have loads of bags, but honestly, my bang-for-the-buck bag is my cloth shopping bag. I use it at the grocery store, gym and when sometimes as a purse if I'm carrying loads of items. They are usually free at some event or other, and friends and family members give me them too. I don't have to worry about it getting dirty or treating it like a precious commodity because it can just be thrown in the wash at the end of the week.
ITA! I use my husband's freebie cloth bag to carry a big binder and hard drive back to my work! It's the ultimate bang-for-your-buck when you didn't have to give up the buck, KWIM?
But I think that for me, bags that would fit the category for a middle class person looking for max value in bags are 1) Cole Haan 2) Coach leather bags and on the higher end 3) Belen Echandia.
I agree with the OP that the low low and high high are not good value, at least from my perspective someone who is middle class with some money to spare, but not loads of it.