Can I purchase the beginner edition first for 0.2btc for my trial run. If I like it, I can then purchase max edition and pay only the difference which will be 0.8btc?
I think you forgot one zero in both cases. The beginner (lite) edition is set as 0.02BTC, while the max (full) edition is 0.10BTC. So as far as I understood, yes, you would be able to upgrade paying the remaining 0.08BTC.
Correct if I'm wrong guys, but those prices are from the holiday special, which means that full version may (and probaby will) increase after Jan 6th, right?
EDIT: br41nbug already answered it above. Thanks mate!