Not my words. Those were Warren Buffett's. Back in 1974. He turned out to be right.

Earlier this decade, he warned about the insane valuations during the Internet bubble and the dangers of derivatives. Correct and correct again.

Last October, he wrote an op-ed piece in The New York Times urging investors to start buying stocks. Aside from his recent shopping spree on behalf of his company, Berkshire Hathaway , he started buying up stocks for his personal account. Though the latest quarter saw him focusing on foreign debt securities, he still picked up shares in Becton Dickinson (NYSE: BDX) and Johnson & Johnson .

The day Buffett penned his Times piece, the S&P 500 closed around 950. Almost a year (and a lot of volatility) later, it's not much higher.

Certainly, we should follow his lead, right?

Not so fast.

The economic numbers are ugly. Unemployment is just under 10%, the annual deficit is adding more than a trillion dollars to our already $11 trillion-plus national debt, and our GDP is still falling. Yet we've just seen the market rise 50% in less than six months. Yikes!

Who's right? Is now another time to invest and get rich? Or is the market a sucker's bet?

Buffett vs. the numbers
Before I answer those questions, let's be clear. This isn't a market-timing discussion. We Fools believe there's no proven way to consistently time the market. Even Buffett admits that he can't predict the short-term movements of the market. He thinks in years and decades, not days and months. After all, he's the guy whose favorite holding period is forever.

Back to the question at hand: Don't be surprised if both the numbers and Buffett are right. The economy and the stock market could get worse from here, but it could still be a great time to invest and get rich.

Huh?

Remember, since we can't time the market, we're talking only about money you can keep in the market for the long term. Unlike Jim Cramer, we Fools have always said that money you need in the next three to five years should never be in the stock market. As the last year has shown, it's just too darn volatile for money you need in the short term.

So, even if the gloomy numbers are right -- if the economy worsens, and the stock market drops even more over the next year or two -- we could be looking back three to five years from now, thinking that now was a great time to invest and get rich.

OK, but how bad could it get?
Before you start putting some of your idle cash into stocks, know that it could get a whole lot worse. Fellow Fool Morgan Housel showed just how much worse in "How Low Can Stocks Go?"

Long story short, the S&P 500 has had long stretches in which it has seen average price-to-earnings ratios of around 8. Even after the freefall we've seen (but after this recent rally), the S&P 500's average P/E (for companies with positive earnings) is 68. Wow.

Here's a place to start
Where, then, can we see some of this market cheapness that Buffett wrote about? Not so much in forward earnings -- Birinyi Associates forecasts the S&P 500's forward P/E ratio at 17. Of course, I don't trust analyst earnings estimates to begin with, and I certainly don't trust them in the current environment.

No, it's at the individual-stock level where I warm up. We have big-time companies trading at low P/E ratios. When I start seeing P/E ratios in the neighborhood of single digits, I get very interested. Take a look at these companies:

Company

P/E Ratio

Archer-Daniels-Midland (NYSE: ADM)

10.4

France Telecom (NYSE: FTE) Continued...