you should ask yourself "why do i want to know these prices?"
the answer you give to this question will guide you on how you can get the real price that suits your need.
for example you want to know prices in order to:
- just know them and see how much everything is worth.
it doesn't matter what you use, you can get the price from anywhere since the accuracy doesn't play a role here.
- to know price of every single token and see what is performing well and what is performing badly that day.
in this case coinmarketcap and all the alternatives are good options as long as you can get ALL the coins information in one place. it is used to do some initial analysis on the market and see where the money is going to.
- to make trades based on recent price
for this case accuracy is the important factor so you can not use places such as coinmarketcap.com and alternatives because they update their prices with a big delay (5 minutes in this case) and for trading you need live price.
for this you should use the exchanges themselves either check the place you trade in or open multiple windows and watch different exchanges (or use their APIs in a program to fetch the prices)
- there may be more cases that i can't think of, feel free to tell us why so we can help better.