The cost for you is marginal or non-existent, and you get an excellent referral system.
When you sell a membership, give the new member a bonus membership (one, three or even more months) he can gift to anyone he thinks might find it useful. You can test it as a surprise after they already joined, or as another incentive to join.
Have a better audience for your website.
A website that shows no content unless you are logged in as a member. Membership is free, but you have to register. No functionality or content are given without registration. It’s a secret “club” for members only.
You would like your VIP treatment the way you like it when going shopping.
A system that senses when a VIP card carrying member enters your store. Immediately a rep is alerted not only to this fact, but they also see their picture, their past purchases, and most importantly, their treatment preferences (approach and “tail” them, stay away until they call for you but be alert, etc.) gleaned from speaking to them and observing them in the past.
There are many benefits to being a member instead of buying. Some are personal access, no substantial upfront cost, always updated, quit anytime, etc. Having a members club is also beneficial for other reasons. For example stable income, attentive audience, etc. there is, however, one problematic facet to having one: you need to keep members interested so they won’t leave.
Build a membership plan that has only one component: you. Give the group access to you in the form of a weekly or monthly interactive (online or offline) group meeting, where you talk a little about your relevant experiences of the past week or month, and then anyone can ask questions, and you answer them. You should also close the meeting with a cliffhanger for the next one, and deliver the one you promised in the previous session. That’s it, nothing else. No Extra content, no new training, etc. just a periodic access to you and your brain.
Have a weekly online live lecture for members. Membership should be a low fee to have as many members as possible. Additional revenues from a commission from lecturers sales. Members can access replays and synopsized replays with just the main points (and the pitch.) This is less about the person and more about the actual help they provide each week.