I think that if there was a guide telling people how much points each game is, it would be very helpful. People could search through the guide for a particular game and it's point amount by typing the name in a search bar. Also, people could mark the game and, once they did, they would be notified if the required point amount changes, be shown how many points that they have, and how many they have left to go.
The reminders tab already does some of this, and you could just look through the BananaExchange page. The prices change very very infrequently if at all, so there's not really a need for a notification for it.