No, there are no extra fees or hidden charges when you redeem your activation code. The full amount is transferred to your balance, which you can use freely however you wish.
If you choose a gift card, product, or option that costs more than your balance, you can easily pay the difference with a payment card. This way, your activation code never goes to waste, and you can always make full use of its value.
Your activation code is therefore completely fee-free, and you receive the full amount to spend on gift cards, donations, or prepaid cards.