Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa., – Volume 13, Page 527, Fatwa No.18521
Question: I hope your excellencies can advise us about using Saudi Net [debit] cards when buying items from stores in the following manner: When the total sale price is agreed upon, for example SR150 (riyals), the card is presented to the salesman who passes (“swipes”) it through a machine he has in the store. The [total] value of the transaction is then debited instantly by transferring the amount from the buyer’s account to the vendor’s account in the same instant, i.e. before the buyer leaves the store.
Response: If the matter is as you describe, then there is no harm in using the mentioned card, so long as the buyer has sufficient funds in his account to cover the required amount [of the sale].
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet ﷺ and his family and his companions.