I use two of the oust fans. Mainly because they are simple...
Got them from Walmart marked down from 7.99 to about 3.49 recently.
No wiring, just remove the scent bottle (make sure it hasn't already leaked on it) and install the included D cell battery. It runs 5 minutes on and 15 off for over a month on the one battery.
not a lot of air movement but gets the job done I think.