Considering carrots are likely to be bought and sold at the 1 meeble mark, I doubt we would allow the price of a golden carrot to me much more than a few meebles above what 8 nuggets and a carrot would cost.
Your logic also applies to things like ALL craftables in the game, whats to prevent people from buying logs and crafting chests and selling them back?
The new shop will take some time to iron out all these issues, however this is not an exploit, it is the very nature of the game.