You said you will be botting agility. Ill give you one piece of advise, DO NOT BOT AGILITY YOU WILL GET BANNED. Agility has a high ban rate. Just don't.
Personally, the only way I would buy an account is if they are trusted with lots of feedback. If you use a middleman with a unverified seller, they can always recover the account back.
If everyone had a custom color name, the value wouldn't be there anymore. Colored names are a privilege that only the most dedicated people get. I think it should stay that way.
The best thing to do is try it yourself and see what works. If you try botting for 7 days a week and then a week later you get banned then you know its to much. Just keep trying until you get something that works for you!