You can be making a rod for your own back if these guys blab to others about getting cheap beer, or even if they get used to accessing cheaper but quality beer. I found when I brewed back in the 80's that most mates couldn't give a toss about how much time, care and ingredients you used, just the outcome that they could guzzle. If they aren't interested in learning to brew over time then they are just after a cheap(er) piss up. Maybe do a few brews where they contribute ingredients, with extras for your personal use later, and they must help on brewdays and show a sign they are willing to take up brewing themselves by buying kit and bottles. Otherwise wind it down with them or it will get out of control, then when you pull the pin you'll be the worst bastard in the world. Just the voice of experience, Cheerz Wabster.