It's not about clearing a sample it's about how much you made from a song to get sued for it, don't expect a pop artist to buy a beat from you unless it's a rare sample that's not owned by the big record labels and it's not the core of your beat.

If it's the core of your beat and doesn't have the same feel without the sample in it then it probably best to just stick to underground or indie label artists to sell your production to.

Don't ever stop sampling, just learn to clean it up, use sounds more than samples, the more you chop up a sample, the unrecognizable it becomes, oh yeah don't use the same ol' sample every rap artists has used since the 90's; also stay away from artists who don't like clearing their songs such as Steely Dan, anything on the Westbound Records label as long as it's done in advance with pay, nothing by The Turtles (or under the name The Crossfires or The Rhythm Butchers), Bob James will clear a sample as long as it's a positive song and has minimum curses.

But yeah you can sample all day on an indie level like Madlib, Pete Rock, etc.