Prices on Coinbase

Hi guys what are your thoughts about the prices of most popular currencies on such exchange platform as Coinbase. Where it is better to purchase bitcoins, Ethereum and Ripple coins? The thing is that I used to take coins on Coinbase. Maybe there are some other sites for exchanging exist where the prices are significantly lower? But it must reliable well-known platforms. Does anyone have the useful information? Please inform me. I’ll be so much gratitude.