There are a fair number of tickets, and the mark-up for 3-400 levels doesn't even feel that insane if they were over $100 to begin with (compared to the mark-up for the better seats). I always preferred to do the last-minute street hustle myself, sometimes you'd find a fan with an extra and sometimes you'd get to squeeze a scalper. Not sure if/how that can be done in the mobile-only era (the fan part, sure, the scalper seems more complicated. And it's still technically illegal on stadium grounds, not sure where that boundary actually is).
I'm kind of torn as I was hoping to go Sunday but that could be the toughest ticket, whether it's a 2-2- series or a potential clincher (for the Phillies, let's not contemplate the other). The weather Philsmania mentioned would definitely be my friend though (that's also how I saw the second half of Game 5 in '08). But with an afternoon game I would think they play it, however long it takes.
The question for me is if Saturday prices will go down Saturday to the same level today's are currently at. I kind of think not, more people can go on a Saturday.