Just wanted to toss in more cents. I am not a student. I like to unwind after a day at my real job by tinkering with web app development; maybe, someday, I will get an idea worth implementing. Your service looks far more robust than I would expect to get for free, but the jump from $0 to $20 is bigger than I am willing to manage when I have a perfectly useable editor on my local machine. So, why don’t I just use it? Because I’m curious and I like to tinker.
So, my two cents? Maybe a lesser subscription for less serious “developers” so they can contribute to the cause even though their total load on your system is minimal. I haven’t looked around enough to know what I would offer for, say, an annual subscription of $50? Or whatever your marketing gurus come up with. Something at login to say “HEY, THIS GUY CONTRIBUTED TO THE CAUSE!” and maybe an extra private workspace to tinker in while having a public workspace to show the world?
Heck, I would pay for that.
But I don’t pay $20/month for the music subscription I listen to 10 hours a day at work.