Being thrifty means being careful of your money and how you spend it. Think twice before you spend, but if you must shop, hitting the sales and using coupons are good ways to be thrifty.
Note the similarity between the adjective thrifty and the verb thrive, and you'll realize that being careful with your money might be an important survival tactic. Everyone worries about having enough — look at how thrift shops have become important sources of clothing and other goods for many people, allowing them to buy without spending a fortune. Being thrifty is a solid virtue, as suggested by the old German proverb, "Prudent men woo thrifty women."