Just make sure you give the buyer a list of terms of sale here is mine for an example
I look at uncleared sample beats as kinda like the same as paid for dj mixes it's still technicall copyright infringement yet everybody does it so it seems
I highlighted in
bold the parts that deal with your question
*PLEASE READ THE TERMS OF THE FOLLOWING BGBEATS.COM LICENSE AGREEMENT 1) The BG BEATS available for sale as mp3 download and non exclusive license remain the property of BGBEATS.COM and are licensed, not sold, to you for use in a new recording with vocals added.
*Any BG BEATS that contain samples from copyrighted works are "uncleared” and it is the licensee's responsibility to obtain sample clearance if so is desired/needed for commercial release.2) The Licensor (BGBEATS.com) grants the licensee (buyer) permission to alter any BG BEATS related to this agreement to suit the individual needs of the new song recorded with the licensed beat.
3) This license does not authorize the distribution of any BG BEATS WITHOUT VOCALS added on the recording being sold/distributed.
Vocals of some sort must be recorded onto the BG BEAT prior to distribution whether free or sold.
4) The licensee *may use* the BG BEATS in compositions such as, making demos,mixtapes, records, remixes, and live performances. The licensee may sell up to 2,000 cd's or downloads of the new recording at which time the licensee is asked to renew the non exclusive license.
5) The non exclusive BG BEATS price gives the buyer an untagged mp3 file of the BG BEAT/s purchased and permission(license) to record vocals on the beat and sell or give away in cd form for promotion as well as display online and sell the final product on own site or itunes store etc etc.
6) The BG BEATS are licensed 'as is' & The Licensor can not be held responsible for any direct, indirect, or consequential loss arising from the use of Beats licensed from BGBEATS.com in mp3 form.7) Completion of a BGBEATS.com mp3 download/non- exclusive license means acceptance of these terms of the BGBEATS.com Non-License Agreement.

Your Pay Pal receipt acts as proof of your non exclusive BG BEAT/s license purchase so be sure to save your Pay Pal receipts.
9) You are requested to list credits as : "BEAT PROVIDED BY BGBEATS.COM" on any cd track listing or mixtape/ liner notes/websites.
10) Questions/concerns can be sent to the permanent e-mail address :
[email protected] include "BGBEATS.COM" in subject.