What is the ruling on the price of a commodity differing in sale according to quantity?

Scholars have differed on the condition of knowing the price at the time of the contract. The majority stipulate it, while Shaykh al-Islam Ibn Taymiyyah held the permissibility of the price becoming known later, provided that this does not lead to dispute.

Accordingly, contracting with electricity companies, where the price is not precisely determined at the time of the contract but becomes known based on consumption, is not valid according to the majority because it involves an unknown price (جهالة في الثمن). However, it is valid according to Shaykh al-Islam Ibn Taymiyyah, because this unknown element eventually becomes known and does not lead to dispute.

Secondly, electricity companies fall under "adhesion contracts" (عقود الإذعان). These are contracts formulated by one party (the company) where the other party (the consumer) has no power to alter them. They are characterized by: their relation to essential goods or services for people, the offeror's monopoly over those goods, the offeror's sole formulation of conditions, and the uniform presentation of the offer to the public. The Islamic Fiqh Academy (Majma' al-Fiqh al-Islami) has ruled that these contracts must be subject to state oversight to ensure justice and prevent oppression. If the price is fair and the conditions are not oppressive, the contract is valid and binding. However, if the price is unfair or includes oppressive conditions, the state must intervene with just compulsory pricing or by modifying unfair conditions.

Therefore, the inclusion of gharar (ambiguity/uncertainty) in this contract – according to the opinion of the majority – does not burden the subscriber with sin.