Facebook friends – dump them all. And that includes family too. Empty your FB out totally. Then charge people to join your Facebook profile.
Make people apply and give their reasons for wanting to join your list. Make it hard for them to do so – thus engendering desire.
As to price, anything from £5 a month to £50, or more. You could offer concessions. But I wouldn’t. People don’t value “free” or low cost.