The watchlist
Follow cards you do not own yet. Watch one from its detail screen.
Watch a card from its detail screen to see it in the Watchlist, with its current price and its recent movement. It is the place for the cards you are hunting, and the list the price alerts read.
Watching is free. Setting an alert on a watched card, so the app notifies you when it crosses a price, is part of Zukan Pro. See price history and alerts.