The Standing Committee was asked: 

A man asked his friend to buy a car for him with cash, then sell it to him for a deferred payment with extra money as a profit. Is this regarded as riba?

They replied:  

If a man asks another to buy a specific car for him or a car that meets certain requirements that he stipulates, and promises to buy it from him, and he buys it from the one whom he asked to do that and takes possession of it, it is permissible for the one who asked for it to buy it from him after that for cash or in installments with a specific amount of extra money as a profit. This is not a kind of selling what one does not have, because the one who you asked for this product is selling it to the one who asked for it after buying it and taking possession of it. He does not have the right to sell it to his friend, for example, before he buys it, or after he buys it and before he takes possession of it, because the Prophet (peace and blessings of Allaah be upon him) forbade selling goods until the merchant has them in his own possession.

Fataawa al-Lajnah al-Daa’imah, 13/152