So I plan to offer my gg (minecraft) cars on my own website. So the sale takes place legally on gg.
As long as there's ingame money clear because advertising is allowed only when it comes to real money trading then it is forbidden. ^^
It depends what it is. If you offer a schematic with cars that you have created yourself, you can also sell this schematic. It's your idea. Whether someone will do that, however, is doubtful, as there will certainly be problems with payment. You also have to exclude liability if the schematic does not work, otherwise it can be expensive.
There are relevant English-language sites where you can offer your schematics. Google is your friend.
You are not allowed to sell Minecraft itself (or generally produced by Mojang). Not even with the hint that it's from Mojang. Mojang prohibits this in its terms and conditions. They want you to buy directly from them.
However, if you've created something completely your own that can only be used with Minecraft without containing parts of the game (e.g. A server plugin), Mojang doesn't mind and you can of course sell it (which is also done) , as long as there's nothing else in it that speaks against it.
Depends on what is being sold.
That too, of course ^^
