That’s a good deal, but I’m afraid estreet plastics has you beat.
$98.82 for 20 glowforge sized sheets. That’s $4.94 per, a 25% savings. If you buy 21, you hit another discount level and it goes down to $4.83, a 27.5% savings.
Estreet has been mentioned more times than I can count on the forum. I wrote up some tips on how to use the forum to find materials sources, you might like #1a here: