gotta serious question for producers who sample

[robbyelliz]

are loops & samples royalty free? for instance some of the loops and kits you find in some forums; or if my boy loans me- a sample cd etc. does a producer such as myself who hasnt purchased these packs yet have to worry about any legal troubles if i alter and compose these loops/arrange the sounds into my own compositions, put a vocalist- singer/rapper to these tracks, do i have to worry about somebody saying "hey those two bass hits sound like my work"?? [this is insane]
do brothers like myself, which i know almost everybody's doing this, but do we have to worry about any legal trouble? cause im thinking if i catch a loop pack that im doing some good work with off a site, then imma purchase the sample c.d. one dude said he'd just use the loops for practice; but to me that defeats the purpose of a sample cd. i can pay for any loop or sample c.d. i use, so im talking about trying to do good buisness with some of these sample/loop cd producers. but there's such threatening hype around this issue, legal processes hurt both parties.....im just saying is it that bad or whats the deal legally with this looping & sample c.d.'s?? please give me some info on this cause i have some good things going for me music wise and i dont need any legal trouble over sampled music.
any feedback is greatly appreciated. call me stupid, call me an idiot, thats fine. but if anybody could give a brother some honest/constructive feedback i'd really appreciate it.
God Bless,