I assume this question apply to stock market too? Price on coins are different on different Exchange? However the price difference should not be much, and the price change constantly. Therefore I should not worry about it?
Coinbase has high fee.
LocalBitcoins has scammer. Price is set by the seller? It means price could be very different than market?
There seem to be many factors at play here which account for the price differences between exchanges. For example, at Bitfinex, the Hong-Kong exchange, the Bitcoin prices were a way higher than elsewhere earlier the last year because they had been cut off from fiat channels. People couldn't withdraw fiat and had to buy coins at a premium.