Just to add an cosmetic special item for someone who buys perm member for their account, non-tradeable or non-giftable.
2nd idea is when a user of the community puts money onto the game develop a loyalty reward system say $10 = 2 loyalty points then when they have enough loyalty points they can then trade them in for prizes or money or what suits and fits the community best without making it op for them either. Which could fit into members shop which was suggested due to paying for member you will get loyalty points and that's the only way to obtain them through cash, but if you're a member you get a set amount of loyalty points each month you maintain as a member, or weekly. Just an idea, tell me what you think! Feedback appreciated.