...
Here is another option:
https://balmahome.com/product/portable-car-ac-system-portable-mini-air-conditioner/
Sorry, but that's just a low efficiency evap cooler. And with it using 150 ml in 4 to 6 hours, it's really low output too.
It just cycles the air inside the car. It will run until it's dry or until the interior air is 'full' of water vapour and no more evaporation can take place, so no more evap cooling. At that point, you need to let more hot & dry exterior air into the interior before it will produce cool air again. You can have hot & dry air coming in all the time, but then the incoming hot is fighting the evap cooled air. BUT, if you can aim its output at you, you have a turn-key 'solution'. A window cracked open a quarter-inch to half-inch or so is necessary to let the humid air out.
The above is why hanging a cloth over the incoming hot & dry air vents works. Instead of chilling interior air, it changes the
incoming hot & dry air into cooler moister air. It always has a hot & dry source from the vent. You just have to keep it damp/wet...
Which is why the DIY bin evap cooler works best when it has the vehicle's incoming air ducted into the bin, so it too is converting the incoming hot & dry air. And if you do that, you don't need the $ for a computer fan with static pressure, as you're using the vehicle's fan to drive the incoming air. So a bin with lid, Dura-cool evap pad, cheap VDC pump, some small PVC to hang the evap pad on, some weather stripping to seal, power the pump from the cigarette lighter, something to duct the incoming air into the bin top. Would work a lot better than that unit, but likely cost around the same or $10 or $20 more, depending on how fancy you want to get.
To get an idea if evap cooling will benefit you, check your temperature & RH on the chart to see what temperature drop you can get.
There's different possibilities for a DIY evap bin, depending on if it's going to be a bin on the front passenger's floor, floor behind driver or behind front passenger, or sitting up on the rear seat folded down. There's also the possibility of a separate bin as a larger water reservoir. It cools more the larger the pad area is, and if the reservoir is insulated (so there's also cooling from the chilled water temperature). So a garage sale camping cooler is another good container to use.