A 5000 btu window unit is less than $ 85 and dehumidifies the air at the same time. I picked one up in a Boy Scout yard sale for $ 20.
Boy, I wish I knew where to buy a unit like that for $85!! I wanted to cool down my garage so I could work there in the afternoons. It's 630 sf with 12' ceiling. I was told minimum 10,000 BTU...the cheapest refrigeration unit of that size was almost $300, and the evaporative coolers (swamp coolers which are basically a squirrel cage fan, a small plastic centrifugal pump and some treated paper pads) were the same or more!!
I finally bought a used window mount swamp cooler, built the frame, ran the water supply and and $325 later I plugged it in... helps a lot, but I found I still need another fan to help circulate the air.
Swamp coolers only work in low humidity areas because they rely on evaporation of the water in them to absorb the heat from the incoming air. If a person lives in a high humidity area, they won't work at all... when we lived in Alabama and Maryland, no one had a swamp cooler... didn't even know what one was.