They cost nothing. I remove my bank cards, my e-mail, phone number if it is possible between leaving it. If it is impossible to remove all paying methods i used - i delete it.
The accounts i use differs. Some of them has about $10-20, few are about $250-500. Summary it is about $2.000-2.500 i think. But it is not fixed sum - i bet a lot and withdraw regularly.
In a public forum i can say tell my opinion. And all of us must understand that it is not a good idea to follow the advices of unknown person without own research.
Firstl, I still think that account trading is risky even though the prices you have given may seem attractive. And if you can delete all that data from the account, why would someone buy it? It is assumed that the account is registered in your personal name, that this name can never be changed, and that the rest of the data (payment card or confirmation address) matches it. This means that the process of change is not possible as easily as we imagine.
Secondly, you are not an unknown person on the Internet since you are a reputed member on the forum, according to your profile. This good reputation gives your ideas a kind of credibility that makes readers trust them to some extent. This holds you (as an honest member) morally responsible for what you publish. On this basis, I advise you to be careful about publishing some suggestions or sensitive ideas.
I count the accounts that i`m using right now. I never sold my accounts. The accounts i leaved - has no any information except my name and no money. In the operation history it is possible to see in-out transactions and that it were maid using the bank card. That`s all - there is no any information about card, when you remove it from payment methods. If it impossible - i try to delete account.
When i visited this forum first time i thought the same, but some time later i understand, that accounts can be stolen or sold for example. That`s why i try to check any information i get here. There are some members, who i don`t need to check, but it is because i know them for several years and see if they change their languages or interests. I think that it is the first rule - don`t believe information from internet without own research.
Anyway i don`t recommend anybody to buy or sell account. It is mostly rejected by ToS and it is possible to be banned.