Reference: http://www.alfawzan.af.org.sa/node/16086
Question: [What is] the ruling regarding selling [goods on the basis of] a deposit (down-payment)?
Response: There is no harm in it. Selling [goods on the basis of] a deposit – being that he buys an item, and he then has a choice [to decide] over a specific period [of time – whether or not to proceed with the purchase]; so [the seller] says [to the buyer]: ‘you pay a deposit to attest [your] genuine interest to buy’, and if he [later] decides not to buy, then the deposit belongs to the seller.
