In Turkish of course but Google Translate is pretty good these days.
It's promoted as an option for people who don't want to use credit(for religious reasons or simply they can't). It's also analogous to the Turkish tradition of housewives gathering at the homes of each other in rotation and giving money to the current host to finance a larger purchase like fridge or something. Its called "Altın Günü" or "gold day" as traditionally they would collect gold, but these days any currency goes.
I wonder if we have optimized away that margin in our amazon and walmartified supply chains and there is less need for bulk ordering.
Everyone bids on what they would pay and then Groupon goes to negotiate a price?
Then everyone waits?
they just buy in large quantities and resell at slightly lower price than consumers can get individually