Each of these tips costs less than $25.

Home 

• Buy and use a CFL or LED light bulb. In fact, buy 5 CFLs and place them in your most frequently-used fixtures.  You'll save $65/yr from the energy savings of those 5 bulbs!
• Check your furnace or AC filter every month, and clean and replace as needed. Dirty filters increase your bills and shorten the life of the appliance. 
• Insulate your hot water tank, hot water pipes, and exposed ductwork in basements, attics, and crawlspaces.
• Seal and weatherstrip doors and windows.
• Try this test:  Close your refrigerator door on a dollar bill. If you can pull it out easily, you may need to replace the door gasket. Tight sealing gaskets keep cold air in and lower energy costs.
• Buy low flow showerheads and aerators for your faucets, and replace leaky faucets. The less hot water you use, the more money and energy you will save.
• Install plastic sheeting over your windows to help conserve on winter heating costs.
• If you have turned your furnace way down, use small space heaters for short periods to warm up areas where you spend the most time.
• Purchase clotheslines and drying racks to help with drying your clothes. The cheaper wood racks might need to be lightly sanded with very fine-grit sandpaper so they do not snag your clothes. To be safe, turn clothes inside out.
• Also shake or snap the excess moisture from fabrics before hanging them up to dry – they will dry less stiff. If drying in the sun, turn clothes inside out to reduce fading.

Transportation

• Keep your tires properly inflated. It can save up to 7 cents per gallon and improve mileage by 3%. Your tires will also last longer.
• Check and replace air filters, and change your oil regularly.