Murabaḥah is a term for a sales contract where the buyer and seller agree on the markup, the ratio between the cost of a good or service and what?
Murabaha Murabaḥah, murabaḥa or murâbaḥah (Arabic: مرابحة‎ ‎ , derived from "ribh" Arabic: ربح‎ ‎ , meaning profit) is a term of "fiqh" (Islamic jurisprudence) for a sales contract where the buyer and seller agree on the markup (profit) or "cost-plus" price for the item(s) being sold. In recent decades it has become a term for a very common form of Islamic (i.e. "shariah compliant") financing, where the price is marked-up in exchange for allowing the buyer to defer payment (a contract with deferred payment being known as "bai-muajjal"). "Murabaha" financing is similar to a rent-to-own arrangement in the non-Muslim world, with the intermediary (i.e. the lending bank) retaining ownership of the item being sold until the loan is paid in full. There are also Islamic investment funds and sukuk (Islamic bonds) that use "murabahah" contracts.
Relative price A relative price forsay, is the price of a commodity such as a good or service in terms of another; i.e., the ratio of two prices. A relative price may be expressed in terms of a ratio between any two prices or the ratio between the price of one particular good and a weighted average of all other goods available in the market. A relative price is an opportunity cost. Microeconomics can be seen as the study of how economic agents react to changes in relative prices.