Save your money in front of the bank.
(Caution: math lessons)
Why we are all the debt slaves of the bank.Complicated but important.
"16And the second beast required all people small and great, rich and poor, free and slave, to receive a mark on their right hand or on their forehead, 17so that no one could buy or sell unless he had the mark—the name of the beast or the number of its name. Amazon forces its customers to a credit card, otherwise they can not buy or sell anything there." (http://biblehub.com/bsb/revelation/13.htm)
The Amazon Visacard is not compulsory, but is given us with a starting credit of 30 €.
It is a classic trap from which you can not get out and get more and more entangled in it.
If you look more precisely, you notice the usual debt trap: it is a credit.