From what i know on the subject, if the said sample plays a major part in a production then it is infringment, and a certain percentage, if not all of the profits from a tune is due to the original artist....Most clearance deals are usually offered in a one time "buy-out" of the sample, or a deal is worked to gain certain percentage of profits from the tune.....This is if you ask for permission first, if you didn't then this plays a major role in fucking you for ripping someone else's song....But as Milo stated above, if your'e not selling a shitload of records then u probably dont have much to worry about, but if your record Hits any airplay or charts well ......This is why electronic music gets by with sampling, Dance music doesn't have widespread commercial money making success (in a sense) so its worthless to nit pick over little samples, and alot of people chop, tweak, effect or whatever to their samples making them hardly recognizable if recognizable at all
But what ive heard some people do to avoid this is simply put 'For Promotional Use Only' or 'Not For Individual Sale' on their records, yet they still sell them ha!.....