I've been broke lately and keep putting off getting a carbon scrubber so I threw one together on quick an easy. I tried pc fans for a little bit and wasn't feeling the design so I gave into using a bigger fan design good for a room.
Tape up shirt sleeves and neck good to fill with kitty...
Construction site dumpsters = enough materials to build an entire grow room, less for maybe light / fan / carbon scrubber would additionally be needed , but even those can be gotten easily.
I ripped a 4" inline fan from a broken vacuum cleaner, bought my cool tube for a buck at dollar general...