Full Collection/ Paid Kits: 100% Royalty Free this includes Major Placements, Beatstars Sales, Private DM Sales, etc.
For Major Placements only credits would be cool in the credit section. But Still No Royalties.

Free Beta/ Free Kits: Full Samples and Starters are Not Royalty Free and proper credits + royalties are required (My Beatstars: Viom)
Everything else inside the Free Kits (e.g Drums, One Shots) are Royalty Free and no need for credits. 
But Royalties do apply to phrases again if it was a "at least 8-Bar Phrase". For Beat Sales Phrases are Royalty-Free.