The niche is Alcohol, It's a " I Love Alcohol " Very active group with lots of wall posts, lots of videos/pictures members have uploaded.What's the niche? If it is a "get tons of friends" group, I'll pay 0,5$ pr 1000 members in your group. - Not saying I wan't to buy your group - just trying to put a price tag on it.
If you have a niche ( bikes, dogs, pregnant etc) it is much more hard to set a price.
To me buying big groups is a waste of money. if your group is more than 5000 you cannot message your members so it's like a big fortune that you cannot reach, I usually close access to our groups when they reach 4900. Important note: to those who are creating groups to be sold, create them on a separate account and sell it with the group because transferred "Admin" status doesn't give the same rights as the creator (cannot change name and cannot auto invite all group members to an event hosted by the group).