On https://apps.apple.com/us/app/apollo-for-reddit/id979274575

    In-App Purchases
    Apollo Ultra Monthly  $ 4.99
    Amazing Tip           $10.00
    Generous Tip          $ 5.00
    Nice Tip              $ 0.99
    Kind Tip              $ 3.00
    Godzilla Tip          $19.99

They may have a separate subscription service that isn't using Apple's. Or it is possible that the page wasn't updated at some point. Those prices, however, are the prices and match the app.