Litecoin is cheaper at the moment to transfer. I'm not sure what fees coinbase charge but it's normally between 3-5% which isn't much at all. Bitcoin network is congested currently with unconfirmed transactions causing the fee to rise temporarily.
oh, but charging 15 - 20USD fee for sending 50usd isnt expensive? thats unreasonable expensive for me
Maybe so but they are covering the fees for when they send Bitcoin too. Bitcoin at the moment is failing as a currency due to the fees that are required to be paid if you want it to be confirmed in a reasonable time. Exchanges have either withdrawn from trading in Bitcoin or have increased their fees.