Hm. I tried Roblox, and it's like what 6 dollars a month and also other fee's for add ons? At least when I checked.
What is Blockland, like 20 for a single pay the everything else is free? Add it up over a year.
But besides how much it costs, Roblox is childish, laggy, and trying to build is like trying to write HTML when you are first trying it. And if all you can do is sit here and tell the other game which is better, well I'm not even going to give you what to do there.
And here's the best advice you'll ever hear: Stay in school.