Sayyidah Aishah (may Allah be pleased with her) says: Some traders came with goods. I said to the Messenger of Allah (peace and blessings be upon him): "O Messenger of Allah! Stop wearing these old clothes and buy new ones, and pay for them when you have the money." The Prophet (peace and blessings be upon him) sent a message to that trader: "Give me two garments; I will pay you their price in days of ease." He said: "Muhammad wants to consume my wealth." He (peace and blessings be upon him) said: "They know well that I am the most trustworthy and the most God-fearing of them all."
This is to be understood as meaning that he made an offer, but the trader refused; he had not concluded the sale. And even if he had agreed, it is more likely that he (peace and blessings be upon him) would have fixed a time, or made an unconditional sale and then paid when he had the means.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11121