I never used G2A before but I will since their prices are good and they accept bitcoin, apparently. Although this information is well hidden under tons of other payment symbols.
What is interesting though is table of their pay fees:
https://pay.g2a.com/downloads/G2APay-fee.pdf Bitcoin is one of the few payment methods without ANY additional fees. Amazing.
I wonder what is meant with donation fee ... (not a native speaker)