Buy air conditioners in winter (especially the portable ones), sell them in the summer.
Buy space heaters in the summer and sell them back on craigslist in the winter.

Of course you'll need to have space to store these items during off season, but if you can manage it, the payoff is good.

A portable AC can be purchased for $100 or less during winter and can easily be resold for $200+ in the summer because these units retail for over $500.

A space heater can be purchased for $10 or less in the summer and be resold for $40 or more depending on the model.


Sammy