I didn’t intend to belabor the point, but I’ve been asked (implicitly), so this is what’s bugging me. I know the economic impact of paying three more weeks for this service is negligible, and I don’t feel cheated or less likely to recommend it to any friends I think might like it, but as a customer still in a trial period of his own, I found it jarring to be invited to extend a better deal than I got to someone who showed even less initial interest in being a customer than me. If that person invites a friend, does their friend get three months free? I doubt it, but the same reasoning would make it advisable. It doesn’t make sense to me.
What this reminds me of is when telecom providers, for example, offer great promotional pricing, but only for new customers, while existing customers don’t get those deals. Really determined customers can sometimes get those prices or at least some discount if they haggle with “retention” departments once a year, but mostly the existing customers are counted on to keep paying “regular” rates without complaining. I’ve always hated that, but I also get it’s how business works. I can’t change it.
However, here’s what has never happened to me:
I have never had a company I’m not already a customer of, offer me a free week of service while I decide whether to sign up, but if I can refer someone else who might sign up, they’ll get a month to decide, without any perk trickling down to me if we both become paying customers.
I knock on the company’s door – free week. I knock on another door for them – free month for that person. I’m not even a paying customer yet, and already there’s a sweeter deal I can’t get because I walked in the door myself.
I love all things JG and will continue to partake, and probably pay for the partaking when I get to those parts, but this difference in trial periods to two different kinds of new customers, still deciding whether to pay, doesn’t make sense to me.
The message I hope Musopia hears from me isn’t, “I’ve been swindled! Give me my pennies!”. I hope the message they hear is, “This better deal for someone else while I’m still deciding kinda sucked a little. Can you fix that?”
“Cheated” is too strong a word for what I feel about this, but I appreciate your framing and already agree with most of it. 
How do you like that music theory course? I’m very close to paying for that, too. I’ve already watched the two free modules so I know I like it, but I’m not sure whether I’d be better off waiting until I’m farther into my guitar journey to reap more benefits from it. I’m in the consolidation stage of Grade 1, so I’m still a noob.