Yes, money is our madness. Last year, we thought we had found a little cushion when I published a book about the life here in suburban America. It sold 12 copies——six of them to my mother. Four other copies went to various aunts and uncles, who used them for martini coasters (杯垫), then sold them at yard sales. The two remaining copies went to perfect strangers. (I think I owe you dinner, whoever you are. Call me, OK? We’ll arrange something.)
As you might already know, a cushion is some sort of pillow. In a financial context, it has the meaning of having some extra money, so any sudden expenses wouldn't hit as hard. They "cushion the blow".
At a yard sale, people just set up shop in their own yard to sell used items, not unlike a small flea market.
Another word for that would be garage sale.