The first listener to call Jim Cramer's "RealMoney" radio show Friday wanted to know about Akamai ( AKAM - Get Report).

The caller said she bought the stock in the high-$20s, sold it at $35, and wanted to buy more on this dip. However, Akamai has already started coming up again and she asked if it is too late to buy more.

"The opportunity to buy Akamai has come and gone," Cramer said. The stock was $31 on Wednesday, but now that it's up to $34 he said he would stay away.

In selloffs like this, he said that people should never buy up. Tech stocks have bottomed and so some are lifting off again, he said. However, machinery is now trying to find a bottom, so he would think about looking around in that group. He added that oil and oil services are still in freefall, but that he doesn't mind buying a little there if he believes the company will move higher once it bottoms.

He called Dun & Bradstreet ( DNB) "the quintessential company that does well in a slowdown" because people use its product to reduce credit risk.

This stock goes up when the Federal Reserve raises interest rates, he added, which is why it's close to its 52-week high and did not go down in this selloff. He believes the stock is a buy.

He said that UnitedHealth ( UNH - Get Report), which he owns for his charitable trust Action Alerts PLUS, is one of best-performing stocks he has ever seen. This is why he just bought a little more.

A lot of people did things in options that weren't right, and this could cause earnings to be restated, he said, adding that he sees a 12-cent restatement.

But he said that the company has a lot of firepower to buy back stock, and that the worse thing that could happen is that the chief executive, William McGuire, will have to leave and give money back to the company. He said that, for him, it made sense to pick up more of the stock now that it's at a 52-week low and down 27% year-to-date.

He told a caller that Google ( GOOG - Get Report) is growing at 33% and sells at 39 times earnings.

"I would be willing to pay 60 times earnings," he said. The stock has been hideous, but he believes there is nothing wrong with the company.

To get your mind around the stock, it makes it easier to divide it by 10 and think about it that way. Instead of looking at it as a $440 stock that fell to $370, which is difficult to swallow, he said to think of it as a $44 stock that has gone to $37.

Even though he believes Google will go higher, he said that he wouldn't buy it until it reaches $350.

He said that GFI Group ( GFIG) is a winner and that the company has solid fundamentals.

The stock is hurting, he said. But that like Google and Goldman Sachs ( GS - Get Report), he said the fundamentals are intact so he wouldn't give up on it.

As for Nektar Therapeutics ( NKTR - Get Report), he said that it is about to launch a new asthma drug, and that this should lift the stock price.

Everything has been going down, so this stock is going down too, said Cramer, adding that he would think about buying this stock in steps as it falls because it should move higher.

He said that Crystallex International is a good story, but that gold prices have fallen precipitously and taken all related stocks down with it.

It doesn't matter which gold stock you own if the sector is bad, he said. However, gold prices could move higher again. With the market so bearish, he said that he would circle the wagons and only buy the highest quality plays. Crystallex is a bit speculative, he said, so if he had to buy the stock he wouldn't buy a lot here.

Boeing ( BA - Get Report) has gone up since he recommended it, and while he still likes the stock he told a caller that the smart play would be to wait for weakness before buying it again.

"One of the things we learned this week is that stocks go down," he said. If you buy all of your Boeing position now and it falls, that would be a mistake. Cramer added that it is smarter to be patient and wait for a pullback before buying more.

Cramer agreed with a caller that diversification is the best sort of portfolio to have and that Procter & Gamble ( PG - Get Report) is the sort of consumer goods company that is important to have in bear markets like this one.

The company sells the sorts of consumer products that people still buy regardless of ups and downs in the economy, but he said that Procter may not be the best pick for a diversified portfolio.

The company reported "a not great quarter," Cramer said, adding that the Gillette unit is not doing that well.

He said that he sold all of the Procter in his Action Alerts PLUS portfolio because the company's fundamentals were not as strong as he thought, saying that he sacrificed it to put money to work in better stocks.

He said he would look at Schering-Plough instead, which he has been buying for Action Alerts PLUS, or at Colgate ( CL - Get Report) as a good alternative to Procter.

To see the most recent edition of The RealMoney Radio Recap in its entirety, please click here. This recap is published every day around 3 p.m. ET.

At the time of publication, Cramer was long Schering-Plough and UnitedHealth.

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."