I am a builder, but I still understand where you’r coming from. I have fun building thats why I price my services so cheap. Sometimes I just drop the charge on people, I guess thats not a good habit though.
I definitely feel that even if you love it, you should be paid a little bit. Even though it may be something you enjoy, your hard work should be paid for, as you did commit time into it. Don’t underestimate your building lol, cause any development component is REALLY important to a game.