There are more than we can think of, and since they all show the price I do not think is important to have all the apps to track down the market, and I think the ones that have been used for a very long time are coingecko and coinmarketcap and they can even update you whenever there is an increase in any of the coin in your portfolio. As for the delay, I don't think have experienced that since I work mostly with the notification they give, and since I do more holding than trading those doing trading are the ones that are supposed to have concern for the market very well and there is a limit set so if it gets to your price of target then it can automatically sell for itself. it is of lesser value to use those apps every time. and if you can not access the two apps google is always there to also update you on the current price of bitcoin. does doing serious trading will need to have those apps for analysis and also monitoring of the price. either way, it is still important for others.