When at the checkout for your groceries, you can buy a stamp worth €0.10, for every €1 you spend. Once you have saved up 490 stamps or €49 – equivalent to a full paper booklet, you'll receive €3 of interest. It's up to you when to redeem and cash out your stamps.
Many elderly customers have been collecting these stamps for decades. Often saving for gifts, holidays or just using it as their savings.
A majority of the younger generation is not aware of its existence. And even when they are, they can't be bothered by collecting stamps – it's annoying and old fashioned.
However, they're leaving quite some money on the table. Young customer could really benefit, since they're not making any money leaving their savings on the bank.