Legal analysis: 1. Value-added tax: tax exemption policy. 2. Personal income tax: I sell my waste products in the market and pay taxes according to the "income from selling assets". Used cars sold in the market are generally sold at a discount. If I have no income, I don't have to pay personal income tax. 3. Contract stamp duty: tax is paid according to the Certificate of Property Right Transfer, and the taxable income is five ten thousandths. Value-added tax is a turnover tax based on the value-added amount of goods (including taxable services) generated in the circulation process. From the tax principle, value-added tax is a turnover tax levied on the added value of many links such as commodity production, circulation and labor services or the added value of commodities. Extra-price tax is implemented, that is, it is borne by consumers, and tax is levied only if there is value added, and tax is not levied if there is no value added.

Legal basis: Article 30 of the Law of People's Republic of China (PRC) on the Administration of Tax Collection, withholding agents shall perform the obligations of withholding and collecting taxes in accordance with the provisions of laws and administrative regulations. The tax authorities shall not require units and individuals that have no obligation to withhold or collect taxes according to laws and administrative regulations. When withholding agents perform their obligations according to law, taxpayers shall not refuse to withhold or collect taxes. If the taxpayer refuses, the withholding agent shall promptly report to the tax authorities for handling. The tax authorities shall, in accordance with the provisions, pay the withholding agents the handling fees for withholding and collecting and remitting.