Musnad Ahmad 1153:2351

Husayn narrated to us, Shayban narrated to us, from Mansur, from Shaqiq ibn Salamah, from Masruq, from Aisha, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "If a woman spends from the food of her house without being wasteful, she has her reward for what she spent, and her husband has his reward for what he earned, and the storekeeper has the like of that. None of them diminishes anything from the reward of the other."