Jim Cramer told "RealMoney" radio show listeners Tuesday that he is always on the lookout for situations no one else thinks about in terms of making money, even a tragedy like the death of Dana Reeve.

The 44-year-old widow of Christopher Reeve died of lung cancer late Monday, and Cramer believes that the company that finds a cure for the disease will win big.

Genentech ( DNA) is the company that immediately comes to mind when he thinks about cancer treatments, including its treatment Evastin, which he called the "drug of last resort."

But this isn't working if people are dying at age 44, he said.

Instead, he said to take a look at a stock he has not recommended in three years, "a drug that may be the answer to lung cancer," and that's Pfizer ( PFE).

The company has a 3.75% yield, meaning it sends you checks four times a year "while you're waiting for something good to happen," he said.

He added that Pfizer's treatment ProMune is about to go into phase III clinical trial, the last phase before FDA approval. If this lung cancer drug works, it may be the best play against the disease.

Cramer still sees money in the Internet, even though The Wall Street Journal ran a piece saying that Internet companies are going to have to ramp up spending to make money.

Cramer said that he doesn't like traditional Internet plays, including Amazon.com ( AMZN), because he says it gives away too many of its services.

He was also unenthusiastic about eBay ( EBAY), which recently bought phone company Skype, and Google ( GOOG), which he now says is too expensive.

But he said it's possible to make money off of these companies as they're forced to spend more to do more.

The equipment at every giant Internet company uses gear from Rackable Systems ( RACK), chips from Advanced Micro Devices ( AMD) and Akamai Technologies ( AKAM) to drive their traffic, he said.

But even though Cramer likes these stocks, he said they are all really expensive right now.

The company to buy right now, because it's being hammered is Seagate Technology ( STX), he said.

It's down 15% from its highs without having done anything wrong, Cramer said. When we have stocks that pull back while they are in bull market mode, you are being given an opportunity to buy, he added.

Cramer reminded listeners that his buying strategy is to never be arrogant, but to buy in stages. If you want 100 shares, buy 25 here, and then wait and buy another 25.

Your broker will not want you to buy in stages, he said. But you must defeat the broker and take advantage of "sales" when the market throws them.

A caller wanted to know if he should be concerned about insider selling at UnitedHealth ( UNH), with its president, chairman and CEO, Dr. William McGuire, selling 2.3 million shares.

Typically we do not get a giant block of insider selling unless something is wrong, Cramer said, adding that it's right to be skeptical when you see a large chunk of selling.

But the stock is still one of his picks, and Cramer owns it for his ActionAlerts PLUS charitable trust because, he said, it's a top-performing, low-cost health care provider.

It saves companies money, and it was instrumental in writing the new Medicare Part D plan, he added. So under the plan, when you buy drugs, UnitedHealth is about 20% of that program.

Cramer also said that McGuire has not been allowed to sell his shares for a long time and that he still owns millions of shares.

McGuire is just taking a little off the table, he said.

Another caller wanted to know about NMT Medical ( NMTI), which he bought when Cramer recommended the stock on his "Mad Money" TV show at the beginning of the month.

Cramer said he likes the company, which he believes is doing more than any other to beat strokes.

But the company just reported earnings and the stock has jumped, he said. He told the caller to sell half of his position and wait until after NMT's conference call and presentation before putting money back in.

Energy Picks

Cramer emphasized to listeners that there's a thing he calls "the invisible world of investing," which is simply life as it exists all around us. However, if you think like Cramer does, you'll find investment potential in the everyday.

For example, when he bought gas and saw that it was below $2 a gallon, he, like many others, felt it was time to get out of oil.

But Cramer also found an investing idea in alternative energy.

When oil prices spike, alternative energy sources rally because people panic about how much they'll have to pay for crude, he said. And, likewise, alternative energy companies fall when oil prices moderate.

But if you take a six- or 12-month outlook, do you really think we're going to discover acres of oil out there? he asked listeners.

He doesn't believe that the need for alternative energy is going away anytime soon, so Cramer recommended buying these stocks while they're weakened by falling oil prices.

These stocks are out of favor right now, but Cramer believes that they could make a lot of money down the road.

Among his picks was SunPower ( SPWR), a company that went public in 2005 and has been "hot as a pistol" ever since.

This is the stock's first big pullback, he said.

He also said to take a look at Energy Conversion Devices ( ENER), which he called "the Whole Foods of alternative energy."

This high-end company has a product called "thin film technology," he said, and GM ( GM) and Toyota ( TM) want to use its products to make their cars more fuel efficient.

And the most popular alternative energy source right now, the place where companies such as GE ( GE) are really focused, is windmill power, he said.

Cramer said that Distributed Energy Systems ( DESC) is the best windmill play around.

Plus, the company has created technology to separate the hydrogen from water molecules in order to create power.

While Distributed Energy Systems has yet to make a profit, which is problematic, Cramer said that its sales are going up dramatically.

"After sales go up, the earnings start happening. ... If you wait for the earnings, then you'll have missed out," he said.

Want more Cramer? Check out Jim's rules and commandments for investing from his latest book by clicking here.
At the time of publication, Cramer was long UnitedHealth Group.

James J. Cramer is a director and co-founder of TheStreet.com. He contributes daily market commentary for TheStreet.com's sites and serves as an adviser to the company's CEO. Outside contributing columnists for TheStreet.com and RealMoney.com, including Cramer, may, from time to time, write about stocks in which they have a position. In such cases, appropriate disclosure is made. To see his personal portfolio and find out what trades Cramer will make before he makes them, sign up for Action Alerts PLUS. While he cannot provide personalized investment advice or recommendations, he invites you to send comments on his column by clicking here. Listen to Cramer's RealMoney Radio show on your computer; just click here. Watch Cramer on "Mad Money" at 6 p.m. ET weeknights on CNBC. Click here to order Cramer's latest book, "Real Money: Sane Investing in an Insane World," click here to get his second book, "You Got Screwed!" and click here to order Cramer's autobiography, "Confessions of a Street Addict."

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