Is it permissible to obtain a discount card from the dispensary by paying ten riyals once to get a permanent 30% discount for all family members?

The buyer of this card pays a known amount for an unknown عوض (consideration), and this is impermissible in commutative contracts. It also carries the meaning of Maysir (gambling) and Qimar (gambling), and is therefore forbidden. Sheikh Al-Uthaymeen was asked about paid discount cards, and he said that they are a type of Maysir because they are based on a غالبة (contest/gambling element), where either the buyer is the gainer and the merchant is the loser, or vice versa, and this is an impermissible transaction.