Pic from http://www.gutterbookshop.com/
A very interesting post by the Gutter Bookshop in Temple Bar discusses why people would continue to buy a book at a higher price in independent shops when they know they could pay less (as much as €3 or more is suggested) in one of the multiples, where it is possibly being sold at a loss. The benefit of the independent shop being nearer, the good vibe from a more personal service, and the hope that because it's one of a limited number of books the owners have chosen to stock it will be a good book, are all mentioned as explanations.
Another element is what might be seen as a kind of reverse loss-leader strategy.
A loss leader is a product sold below cost to attract customers, and the reverse of that, I'm suggesting, is a consumer buying at a loss to themselves in order to encourage more sustainable business practices in their locality. The customer takes a hit on a number of purchases in order to attract into their community/society/economy better businesses (ones that operate in a less capitalist fashion?) - they might pay their staff better; they might stock more ethical & environmentally sound products; they might use their profits to purchase goods locally rather than transferring them off to the bottom line of a fat-cat holding company in some far off land.
So, it's just an elaboration of the idea of shopping locally, of supporting local businesses, doing so very conscious that it's costing you more in the short term but benefiting you and your community more in the long term: an investment in your future and society's future.