There is no difference, he got confused by an ingame message apparently. There's only one kind of Goldmark. You can either buy it or watch ads for it on mobile, or so I hear.
There IS a difference between paid for GM and GM won in games or gotten through watching videos. Bought GM can be used to help your team mates in games but Free GM cannot be used to help others, it can ONLY be used on your units, provinces or things like that.