The IRS is going to keep track of all of your transactions over $600. If you buy a car and then a few years later sell it. They will view the proceeds of the sale as taxable income. It will be your responsibility to prove its not income. They’re going to be inside E-bay, PayPal etc. So keep your receipts.
With the government’s digital dollar. You will need their permission to buy /sell things. Need to ask the federal reserve if you can sell you stocks/buy any stocks.