It would never be enough for Arthur. Arthur wasn't pleased with his hundred Raks either, especially since after he bought all his upgrades (it is important to have a strong weapon, after all) he didn't have enough left over for the link charm or the memory charm for Merlin. Even if he did sort of enjoy the expression on Merlin's face every time Arthur said his name, there was something unnerving about Merlin using his title all the time to address him.

He nods once, "Can't have you wandering off on me and getting yourself in trouble, this is the best option," and the easiest way to keep an eye on him, no matter how permanent.

Arthur listens patiently all throughout Merlin's little rant, he finds it kind of humorous to be honest. He's so frustrated over it Arthur is expecting him to have a tantrum like a child, "Are you quite done yet? If you would like to purchase the memory charm first we can do so, but I imagine the link charm is more useful for you now as you're probably even more useless now without your magic and with this I can protect you even if you are stupidly in a different school!"

He pauses, maybe he said too much.