All photos and videos published on 99CUTS can be used for free. You can use them for commercial and noncommercial purposes. You do not need to ask permission from or provide credit to the creator or 99CUTS, although it is appreciated when possible.
More precisely, 99CUTS grants you an irrevocable, nonexclusive, worldwide copyright license to download, copy, modify, distribute, perform, and use photos and videos from 99CUTS for free, including for commercial purposes, without permission from or attributing the creator or 99CUTS. This license does not include the right to compile photos or videos from 99CUTS to replicate a similar or competing service.
Even though credit isn't required, 99CUTS creators appreciate a credit as it provides exposure to their work and encourages them to continue sharing. A credit can be as simple as adding their name with a link to their profile or photo / video:
Video by Maciej Loch on 99CUTS