These accounts are personal accounts and, the activity may go up a little bit but it wont go up much. So yea your not gonna buy the account and be able to post almost to hero or anything like that,
I know you said this, but as you said the activity is 300+, how many months do you think it will take for the accounts to become Heroes? Hero member with good trust could sell for a lot. Neutral sr accounts go for around ~0.3btc, so if your accounts will become hero in the next 3-6 months, then the price seems reasonabble.
