In the mental_floss morning cup o' links: The Washington Post has an interesting piece about the cost of poverty. Not "cost of poverty" as in "tax dollars spent on the indigent," but as in the poor often pay more for basic necessities.
Some of it is familiar if infuriating, like the insane, evil fees for payday loans (an effective annual interest rate of 806 percent!) and check cashing services that are the only option for people without bank accounts. Some of it is not surprising if you've lived in a not-quite-yet-gentrified urban neighborhood, like the increased prices at urban supermarkets and smaller shops. And a lot of it just makes sad sense when you think about it -- when public transportation is your only option, traveling in search of better prices on milk and bologna isn't really possible.
If middle-class folks, who are used to getting a response when they complain, had to put up with unreasonable markups on breakfast cereal and effectively useless public transit, something would get done. Maybe more intentionally mixed-income neighborhoods would help.