[Rain Man]

Interesting question. My theory is as follows.

As soon as checks are issued, a number of people will retire, and they'll be the people who really can't afford to retire. They'll spend a bunch of money, inflation will increase, and they'll end up poor.

Prices will rise quickly due to labor shortages in low-wage jobs and the decreased value of the dollar.

The inflation will dilute the value of people's retirement accounts, so upper middle class people will either see no change to their station in life or will have a more difficult time retiring. Middle class people will see a bump in their savings toward retirement, and will likely make a splurge purchase or two. Inflation will dilute the cost of a mortgage, so 25% of the population will pay down or pay off a mortgage, producing a lot of cash in banks.

The banks will make money available at a very low rate since they're swimming in money. Low-income people will want to buy homes en masse, which will create construction jobs at inflated wages, but mostly will drive a big housing price increase. This increase will freeze out low-income people from buying a home while increasing the nominal value for current homeowners.

Lots of people will buy gadgets at inflated prices, with much of the profit going to China.

Rich people will have inside information that it's coming, so they'll convert their cash to tangible goods and will ride inflation up to make a killing.