In the case that the bitcoin needs to be transferred from one wallet to another, there can be a hefty fee for this. In order to transfer money from one bitcoin wallet to another it is necessary for both wallets to agree on a certain price. This is something that all users must do in order not to face these high fees.
There are many exchanges which offer all their service at low rates via credit card or PayPal without any extra charges. Many companies even allow free transfers between various altcoins and bitcoins, however, there can still be a pretty high fee associated with it if you have chosen a very large amount of cryptocurrency when exchanging your bitcoins into altcoins or vice versa. Before choosing an exchange where you want your funds being transferred from one wallet platform to another, take note of how much it will cost just so you know what risks may come along with using such exchange services in the future.