Everybody in here is freaking out about devs having to eat are entirely missing the point that the devs are already eating thanks to ad revenue they introduced into their own app. Having to pay to remove ads isn't supporting the dev because the dev is already supporting themselves with ads. Call the cash grab a cash grab if you want, but understand that this is what it is.
What exactly is the point you are trying to make? Whether the dev gets money via ads or subscriptions doesn't change the "devs having to eat" aspect. How does it become a cash grab when ads become involved?
Asking for $20-100 for an ad free experience and then couching it in terms of "devs gotta eat" is the cash grab. That's why there are ads in the first place. The point I'm making is that trying to make it into a guilt trip is sleazy. There are all kinds of free, ad free alternatives. I'd personally recommend liftoff. They don't have ads and they're not out here trying to imply I'm taking food out of their mouth for using the app without "donating".
$100 for an app is a cash grab no matter how you slice it. Period. End of discussion. $20 for ad free is arguable, but it's way more donation than actual financial support of the devs. That's what the ads are for. So yeah, imo asking for donations on top of ad revenue is grabbing for cash. The $100 version isn't even debatable