There are many online wallets like Xapo and Coinbase that do not charge any transaction fees or they pay that fees by themselves. I want to know that how would they profit from paying for their user's transaction fees ?
If no fees is charged then the transaction take a much long time or even might get cancelled !
They charge pretty good for people that want to exchange bitcoin there, they have some fees when you deposit money there or when to buy bitcoin and also a fee when you want to withdraw your funds so pretty much their profit is here.