Well you have to ask yourself if you want fake friends or you want to run a business where your hard work pays off. If they care about you, then they understand this is your livelihood and you do not have a 9-5 job to fall back on. That too allows them to see that you're a bit beholding to them, so they're taking advantage of your circumstances by asking for more. Its time to ask yourself how hard do you want to work for nothing or if its time to find new band members because its only going to get worse the more you allow it. In truth you never should have given them a percentage of the merchandise because that allowed them to put eyes on something that is negotiable. If the merchandise is created and/or financed by you to keep the business afloat then you must maintain that model to keep it moving forward.

If this is your business and thus your band, then take control and get some new members. Their entitlement streak is obviously more important than your well being. You deserve the fruits of your labor, not the session players who just show up and collect a paycheck. Stand up for yourself and the work you put into this. If this ruins whatever perceived "friendship" you had with them, then so be it. There's a greater principle in play here that none of them are willing to see. And again honestly they don't sound like such good friends if they don't want you to flourish for all the hard work you do. They're taking advantage so you need to cut them loose.