buying on a hand-to-mouth basis

例句：

1. 1. They decided to buy a new car for their family.
   他们决定为家庭购买一辆新车。
2. 2. The store is selling a variety of products at discount prices.
   这家商店正在以折扣价出售各种产品。
3. 3.She bought the dress from the local market for $50.
   她从当地的市场以50美元的价格买了这条裙子。