One thing I have not seen noted in this thread is the difference between an indoor ceiling fan and an outdoor one. If your garage is exposed to outdoor conditions (not direct rain or snow but rather high humidity, hot, dusty at times, etc.) you will be better served getting an outdoor classified fan which is made with materials that are less subject to corrosion, etc. I pooh-poohed this when I put fans on my porch but went with outdoor rated fans anyway, now many years later I'm glad I did because indoor fans would have been "eaten up" by the humidity dust, and bugs, etc.
So just taking a spare indoor fan and putting it in the garage may work for a while, but maybe not, depending on where you are.