How did you determine the account is worth over $300, especially if it is a tier 0 account. An account that is respected by people is not the same as the person behind the account. If it is that well known as you say, then if an "enemy" gets wind that the original owner is not in control of it what are the chances it will get reported as a "sold account". To me the groups have no value if I am taking over the account. I would be shutting them down anyway.
Does it have AP? How many products are in the catalog currently? Are any of them BM products? Does the account have a name change token?
Does it do much sales on a monthly basis? How many credits come with the account if any?
What kind of inventory does the account have, clothes, furniture, avatars etc? Does it have any black market items in inventory? (That may increase value a bit if it does)
Your ad posting says that conditions apply, but you don't list the conditions in the ad? What are the conditions?
Will this sale include all the things that must be included to sell an account on the IMVU Mafias? Email account and all the other conditions recently posted?
Best I would offer is $50 USD, if it has AP, I get the email address it is registered with, what birthdate was used, and the age listed for the avatar is at least 25 years old. $30 if it doesn't have AP but comes with the other things I listed.
HitGirl
Whens this bidding end????
so I apologize. 
Not some thing I do very often.
