Yes givestar charge processing fees.
givestar processings fees are as follows
For online card payments
1.9% + 20p for UK credit and debit cards
2.9% + 30p for International credit and debit cards and American Express cards
For in person card payments (Tap to Donate)
5% + 20p for UK credit and debit cards
6% +30p for International credit and debit cards and American Express cards