I'm really really having fun with this!! My high score is 284 300 on hard mode (on easy mode I got up to near a million before I quit early and went up to hard mode lol). Definitely worth throwing a buck or more at this.
Also I spent a while reverse-engineering the scoring:
1: ADEILNORST
2: CGMPU
4: BFHKVY
8: JQWXZ
And then the score for a word is letter_total * 100 * 2^(word_length - 3). (No guarantee that I didn't misplace a letter or two in the above table.)
EDIT: Ok I just got 297 800 but only because I got fuckin' ANTIQUATES, worth 230 400 alone (and lost soon after lmfao)