Now I am reading about how to use the device, I can see that there is a 4.25% transaction fee for buying and selling (!)
Like DdmrDdmr pointed out, what you are complaining about is not with ledger, it's with the exchange they are affiliated with.
This is exactly the same thing during the days when coinomi wallet was still popular and used by many, they had an affiliation with two exchanges which made it possible to swap between crypto currencies right inside the wallet app, one of those exchanges I believe is shapeshift - fees for this swaps were really outrageous, so what i used to do is move my funds out of coinomi to an external exchange, buy the crypto currency I want and then withdraw it back to coinomi - withdrawal fees on centralized exchanges in those days were even more cheaper than they currently are, so many you can consider doing same instead of returning the device.
