Assalamu alaykum
Is it permissible to pass through cashback sites (such as Quidco or TopCashBack) when making a purchase. This works by passing you through a link, which is tracked. Once you make a purchase, the retailer informs the cashback site of this. After a certain number of days (sometimes months), the cashback site puts money into your account for making a purchase through its affiliate link.
I have always wondered whether this counts as a secondary contract within a contract, or whether it falls under the money now for money later rulings ? I would be grateful for any clarification on its permissibility in shariah.
JzkAllahkher
Nawaaz