Facebook BM ?

Hello all,

I have seen people selling Facebook BM accounts around here, What privilege's does this account have? I mean does this mean when I buy this type of account I have access to a said amount of credit on it ? And I will just be paying for the account only and can use the said $xxx on one of my pages ? Is it safe to use on a legit page ? will there be any issues for that page in future ?

Please don't hate or be mean to me