Why will you go for a paying app notifier when there a lot of free ones that will give you what you need? I have been using CoinGecko and binance and they always deliver what I want anytime.
Binance does that, you can set the percentage increase or changes you want in the coin, so that you can be alerted immediately. Another good app I recommend for that is MEXC exchange.
Binance, CoinGecko, MEXC are all good recommendations for what you want.