While serious gambling (赌博 - dǔbó) is illegal in Mainland China and often carries a strong social stigma, the act of 打赌 (dǎdǔ) is an extremely common and accepted social activity. It's a key part of informal social interaction. In Western culture, a friendly bet might end with a simple “I told you so.” In China, a 打赌 is often used to add a fun consequence to a disagreement, reinforcing social bonds. The stakes are rarely significant amounts of money. Instead, the loser might be expected to buy the winner a coffee, a bubble tea (奶茶 - nǎichá), or treat them to the next meal. This transforms a simple argument into a shared social experience. It's less about the prize and more about the interaction, the fun of being right, and the good-natured “face” (面子 - miànzi) that is won or lost.
打赌 is used constantly in informal, spoken Chinese. It's the go-to phrase for any casual wager.
The connotation is almost always neutral to playful. It is rarely used in a formal or serious context.