No. If the beats used are recognizably from these other artists' works, that's copyright infringement, regardless of whether the uses are free promotional giveaways and not for sale. That might limit the damages, but then again, such willful infringement could result in discretionarily increased damages of $150,000 per work, as well as punitive damages.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.