Imagine a banana in a supermarket. It costs $1 for those paying with Visa, $3 for those paying with MasterCard, 
and $32 for those paying with cash. You can’t sign up for Visa until you’re 65, and you can only get a MasterCard if you have a nice employer or a decent income. Worse, customers have no idea that such price discrepancy exists. They don’t even know how much they’ll pay for the banana until long after they’ve eaten it…………………