Skin Capsules?

So i saw this thing saying that when you are leveling and everything you have a chance for skin capsules etc. Ive heard of some people getting some before my level (110 now) so i am curious.... is there a specific level that you are more likely to get a skin capsule? or is it based on overall levels of everyone in league? or how does this work?

been sitting on all champs for a while now and so some skin shards mixed in from time to time would be quite nice.

I do admit that the champ shards at a high rate is also nice for my m7s im working on, but pretty sure at least some people would like even a random skin mixed in by level 110.