'RealMoney' Radio Recap: Testing the Limit

People want to know how to trade on stocks mentioned on Mad Money, Jim Cramer told his "RealMoney" radio show listeners on Monday, referring to his CNBC television show.

"Buy the stocks I recommend only if you can get them within 25 cents of where they closed that day," no matter how good the idea sounded on the show, Cramer said.

He added that he would use a limit order on anything bought during or after the show, and that it would be "pure, unadulterated foolishness" to use a market order.

"Market orders are strictly forbidden in this business ... you will invariably pay the highest price, far more than you ever expected," he added.

And while some of the stocks mentioned on Mad Money will move higher over a period of days, "most will spike and then go down ... and leave you with a loss," Cramer warned.

He said that a company like Rediff(REDF Quote), which goes up $10, is the exception.

He also said that you can't get involved with after-hours trading and buy something that has moved much higher than it was a few hours before, and that's because the odds are against you.

This is a game where even things like modem speed count, Cramer said. When he was at his hedge fund, he didn't think there was anybody faster than he was, since he had some of the most advanced technology in the business, but even he rarely got the price he wanted.

After-hours trading means "you'll be going up against guys like I was at my old fund," Cramer said.

Dykstra's Dugout

Lenny Dykstra, the "Disciplined Trader" and celebrity investor contributor for TheStreet.com, joined Cramer to talk about his picks for the week.

Dykstra buys calls, rather than a company's stock, because purchasing control of the shares gives him exposure to quality stocks for a lot less money.