It's fairly safe to assume that all third party reddit apps will be shutting down. The price they've been quoted for API access is simply too high, and I don't think any of the devs are rich enough to keep it running out of their own pockets. I wouldn't be surprised to see some apps try to stay up, but I highly doubt they can last long term.
Either that or they'd have to start charging each user tons of money, and/or disabling free users entirely.
In the recent AMA it was said that apps that focus on accessibility might get free access, but based on what devs are saying about having trouble getting in touch with anyone at reddit, I wouldn't get your hopes up.
Find it hilarious how perfectly this solution solves all of the problems reddit spoke about.
Reddit not profitable enough? Not enough premium subs? Third party app users can't view ads? Api use is too high and you're not making money off of it? Making premium a prerequisite for third party app use hits all 4 birds with one stone lol.