You can buy an account on Auction section also to start with a highest rank account, so you can join a Signature Campaign since now and start earnings some satoshis, good luck!
I personally would not suggest buying an account. I think it is a shady world in those who deal with accounts being bought and sold. Take a look in meta and you will find different situations from buying/selling of them that are not good - https://bitcointalk.org/index.php?board=24.0 . And person could come back one day say account was hacked and possible take account back from you.
And even if you end up with an account though it with no problems a LOT of them are crap on posts. You will find some with huge amounts of offtopic like what did you last drink, what music you last listened to, etc. Just posts that obviously meant to boost activity level. And when applying to a signature campaign the better ones will see this and not want you.
So long story short I would raise a account and put effort into it. Don't look for some shortcut though buying account.
I understand that some people steal accounts to resell, but I don't see the accounts market as a shady world. It's just adviced to buy an account from a trusted person to avoid this kind of hacked accounts issue.
And when someone join a Signature Campaign and start making crap posts the campaign just ban those people without chance to come back.
The point is: Have a ranked account isn't sufficient, your future posts will be the real test to see if you will be able to earn money by posting or not.
If the posts are constructive and the account wasn't stolen, no problem, that is my opinion.