I live in Brazil and it is impossible to buy fresh mushrooms here, so I would like to try growing my own. I have done a bunch of reading, and it seems like you need temperatures of 55 Fahrenheit to grow them. The ambient temperature here is 85 degrees. We do keep one room air conditioned at 75 degrees. Would this be cool enough to be successful?

Any tips you can give me would be most appreciated! (Even a place to buy the spores in South America, would be great!)

Oyster being the easiest, all you need is a pasteurized media, various plant matters, here happen to be straw, you might have to experiment with what works for you if straw is not readily available. Straw was chopped short, put in a larger wire basket, made my own from wire mesh,..then put in a stainless tank with water and boiled, [outdoor]. Keep your hands sterile,..then put in plastic garbage bags [sterile], when cold, inoculate with spawn.
Whole straw bale works also, bale emerged with weight in water for a couple of weeks, wasn't pasteurized, it worked pretty good. [fresh straw]
Shitake was grown on hardwood sawdust or poplar logs.

In the beginning I bought spores, later I made my own with grains. I did join a course for a couple of day's near Vancouver, BC..this helped.

Not sure about temperatures, .high humidity is good, I started first in the shed, [summer], later I build something similar but larger with a automatic mister.