The uncle ben's method is really only worth a shot if you're really pinching pennies. It will save you a pressure cooker and mason jars, but you will still need a still air box, fan, shoebox or other bulk containers, scissors, sterilizing equipment (anything from lysol to isopropyl), coco coir, space heater, temperature controller and thermostat, etc. I had contam issues with uncle ben's and had my mycelium run out of steam and dry out before fully colonizing the bags, but haven't had any problems since I switched to mason jars and an instapot. Brown rice is also not the best media for mushroom growing, I've had much better results with wild bird seed and rye berries.

Cutting corners is generally not the best idea with shrooms, they are very sensitive to temperature, moisture, and contamination. It's not like growing pot where you have time to react if you mess something up, most of the time you are dead in the water with shrooms by the time you realize something is wrong.