No. Buying the sticker from someone does not grant you license to use it for commercial use.
You would (or your lawyer) have to contact the copyright owner and ask for a license to use the copyrighted character. If they deem your product to be within what they see fit, and they approve your use of it, then, you would contract to use the character only as specifically outlined in your license agreement.
You would have to get a license for every copyrighted character.
They have to protect the integrity of their property, and make money off it.