Wang Jiang bought electrical appliances from a businessman. Although the microphone is a gift from the merchant, it is actually an additional condition for Wang Jiang to buy electrical appliances from the merchant, that is, the subsidiary obligation of the merchant. Although Wang Jiang did not pay the microphone to the merchant, the payment obligation has been transferred to the goods (i.e. electrical appliances) given by the merchant as a prerequisite. Therefore, the merchant should bear the civil liability brought by giving away the microphone, that is, replacement or compensation. Article 2 of China's Law on the Protection of Consumers' Rights and Interests stipulates: "Consumers' rights and interests are protected by this law when they buy or use commodities or receive services for their daily needs; Matters not provided for in this Law shall be protected by other relevant laws and regulations. "From this law, we can easily see that valuable buying and selling and services between consumers and businesses are the premise of the formation of consumer legal relations, and their values include direct value and indirect value. The so-called indirect price refers to the fact that when consumers use goods, although they have no direct rights and obligations with the producers and sellers of goods, they still obtain the owners of goods through valuable exchange. As we all know, the common promotion method used by merchants is to give gifts with a certain value when selling goods (that is, "buy one get one free"). There is no doubt that the goods sold are protected by the Law on the Protection of Consumer Rights and Interests, but whether the law can be applied to the gifts given by merchants is not expressly stipulated in our laws. Judging from the microphone given by the merchant in this case, it is not free, but a conditional gift, or a gift with a burden (obligation), that is, the donee Wang Jiang pays the electrical expenses, or the donee Wang Jiang is obliged to buy electrical appliances from the merchant when accepting the microphone given by the merchant. Therefore, the donated microphone accepted by Wang Jiang is still obtained through valuable exchange. However, Wang Jiang does not have to bear the payment obligation of the donated microphone itself directly, and its payment obligation has been transferred to the purchase and sale of electrical appliances as a prerequisite for the donated microphone. Moreover, although the Consumer Protection Law does not directly stipulate the gift in sales, it does not mean that the donated USB flash drive is not regulated and controlled by other laws, nor does it mean that the Consumer Protection Law absolutely excludes it. In this case, the merchant used the promotion method of "buy one get one free" to give the defective U disk to Zhang who bought the computer. This gift is obviously a conditional gift. This condition is that Zhang must buy a computer from a merchant. According to Article 19 1 of China's Contract Law: "If the donated property is defective, the donor shall not be liable. If the donated property is defective, the donor shall bear the same responsibilities as the seller within the scope of obligations. If the donor intentionally fails to inform the recipient of the defects or fails to guarantee that there are no defects, thus causing losses to the recipient, he shall be liable for damages. " According to the regulations, merchants must bear civil liability for Zhang within the value range of the USB flash drive. To sum up, the merchant in this case should bear the civil liability for replacing or compensating 240 yuan for the express value of the USB flash drive presented by Zhang who has bought the computer.