I guess the question is, what would you need licensing for? Do you mean when it comes to buying graphics or fonts for your stickers? Or do you mean using someone else's design?
"Free for commercial use" can be tricky so just check the fine print. They most likely have restrictions on how many impressions you can make or where/how you can apply it. Also, the quality of "free" anything usually isn't that great so there's that to consider as well.
Good luck!
