PaterAlf: It has always been 5.99$ US and 9.99$ US. The prices in Europe also went up, because the Euro lost a lot of value in the last few months. But it isn't a price hike on GOG's side, it's simply the result of currency exchange rates.
jahoult: Lol our dollar didn't suddenly drop in value overnight. A falling AUD might be the reason but GOG still clearly made the decision to raise the prices by a fixed amount.
It would have been nice of them to at least explain that they were re-evaluating their overseas pricing based on current exchange rates, rather than just assuming no one would notice/care. 27.5% is a massive jump and I'm pretty sure it's the only notable price change they've introduced since they started listing in local prices. It's not as if their prices regularly fluctuate or anything.
Yes, they do it by a fixed amount from time to time. Change normally includes currency losses from the former weeks and isn't exactly the actual currency conversion because they take into consideration how the currency will develop.
For me it's normally cheaper to pay in US$ after such a change and a little cheaper to use the € in the weeks before they change it again.
And there is a thread where they announce and explain the new prices. Will see if I can find a link for you.