Now I'm really and utterly scared. A few hours ago Pathfinder Imperial Edition cost $37 approximately, now I see a price of $85!!! WTF??!!!! Is it a site glitch or what? I really don't understand. Some games still have the same price while others have gone through the roof. I'm from Costa Rica and I have my currency for dollars, because this obviously has to do with the currency exchange rate if it's not a glitch. Can anybody give me any information? It would be really appreciated!

Not exchange rate, regional pricing. Costa Rica probably had a regional discount so far which was now removed, as the base price for that game is $84.99. (Which is still something, as over here it's $98.49, because we're so very rich, ya know?) GOG seems to be on a spree of changing regional pricing matrixes lately, and adding more regional pricing, often with regions paying more than base price, for old games that so far just had the basic system with discounts for RU/CIS and South America (and maybe also China).
Alternately, GOG is also having a lot of trouble with geolocation lately, it would seem, so it may be that it suddenly decided you're somewhere other than in Costa Rica and get charged accordingly.

Pathfinder Imperial Edition costs Australian $99.95 (VERY EXPENSIVE) I do believe the makers of the game set the price, gog is just the store front. I certainly won't be buying the game and it dosn't appeal to me- but treating the customers like milking cows certainly dosn't want me to rush out and buy their games anyway.

The site is probably confused about where you are and "sent" you to the default, which is United States with US dollars. Try to refresh your account and see if you have again regional prices: https://www.gog.com/user/refresh