On Amazon, you can buy 50 cable holders for 20 cents a piece. In this video, I show how to make one for 2 cents. If I need just one I can make just one, using only readily available materials.
However, note that usually, cable holders on Amazon allow you to detach and reattach cables easily. If you frequently need to detach and reattach, this solution isn't ideal.
This approach isn't limited to cables. For example, you can attach a similar loop to the back of a kanban board such that it can be held up by a pole:
