why pay $400 for something that you can do manually by yourself?
First if all if you haven't noticed that you as a user with higher rank you have the ability to put more text as a signature below. As this forum is monetized by ICO campaigns and services regarding bitcoin then you earn money for advertising on bitcointalk forum. Selling accounts is highly risky because if noticed some accounts here are called trusted members and if they notice that there was an account trade done they will flag your account by simply giving you negative trust. With negative trust your account is limited to enter less campaigns. So there is huge risk involved if you are looking into buying one, not to mention that there are many scams around as well.