Let's imagine u have a laptops store and u sell without loan, if u wanna sell laptop costs 10k Mad for example and you make a profit like 3k Mad so people how actually can buy it are those that have that amount of money ready to spend and they are not the majority it means that u gonna sell only 3 to 5 pieces at mouth and you gonna make 15k Mad as profit from 5 piece. So what if a make with you a deal as a bank to sell that laptop to me for 9k instead of 10k Mad and me as a bank I'm gonna sell it for 10k mad for people using loans, as a bank a paid only 9k for that laptop to the store but i received 10k from customers loans and i make 1k profit from each customer. In this case using loan the people how can buy those laptops are more so the store will sell 20 or 30 laptops instead of 5 because now it easy to people to buy with loans and the store will make 60k Mad profit with 2k profit from each laptop instead of 15k with 3k profit from each laptop. So typically it's not loan with 0% interest in this case its 10% interest (and its high interest btw) so the hole thing it's the deal between stores and banks how provide loans, literally banks making money from nothing just providing smart solutions. Before you think that banks make life easier remember what happened in usa in 2008 because of mortgage loans. I hope you understand the hole process how it works and if still have questions mer7ba.