So after some searching I have finally found a completely free option to have forum notifications for users. Within the next few hours we will be discontinuing support for Pushover in favor of using Telegram for our notifications. The chat client is free and links to its download for Android and iOS will be at the end of this post.
To configure, get Telegram and open a new message to @MoltenAetherBot, the bot will then give you a chat ID number. Paste that number into your user settings page under “Profile”. The text box should be at the end of that page and titled Telegram Notifications.
Download links for most every platform can be found here. Again, it is entirely free.