Not every room has AC, and it isn't always worth running. Here are cheap cooling solutions that actually help.
A room heats up, has no AC, and a split unit means big cost and installation.
A strong desk/tower fan for airflow, or a portable evaporative cooler (with water/ice) for a small room — portable, no installation.
High airflow (CFM), low noise for a bedroom, and USB/rechargeable if you want full portability.
A fan facing an open window in the evening pulls cool air in — far more effective than a fan mid-room.