Whether you rent a small apartment in the city or live in a three-bedroom country cottage, greening your home doesn’t have to strain your wallet. As I was researching my book Generation Earn: The Young Professional’s Guide to Spending, Investing, and Giving Back, I interviewed hundreds of experts about what works, and what doesn’t, when it comes to living more sustainably—and frugally—today. Here are seven ideas to get started:

Use less energy. Small changes, like closing doors to unused rooms or turning off the air-conditioning during the day, can make a serious dent in utility bills. So can unplugging appliances, turning off lights, and shutting down computers at night. A power strip known as the Smart Strip automatically cuts power to devices that don’t need it when they’re off. It saves the typical family about $15 a year.

Change light bulbs. Substituting compact fluorescent light bulbs for incandescent bulbs will save around $40 per light bulb over its lifetime, which means it pays for itself after six months. New developments means the bulbs offer a glow that’s more similar to natural lighting than they did previously.

Make cleaning supplies from scratch. Even Martha Stewart endorses this technique. A bowl of vinegar or simmering lemon rinds can absorb smells just as well as manufactured air freshener. Scrubs made out of baking soda and water make kitchens sparkle just like chemical-laden cleaners.

Renovate with recycled products. Habitat for Humanity’s “ReStores” sell surplus materials at a steep discount. (Sales go toward funding more homes for low-income families.) Web searches for “architectural salvage” can also turn up gently used pieces, since some new home owners end up redoing the kitchens of just-built homes.

Make toilets more efficient. If you don’t want to spring for a new low-flow toilet, then transform your traditional one by dropping a soda bottle filled with sand or water in the tank.

Insulate yourself. If you’re a homeowner, you can take advantage of federal tax incentives to make your home more energy efficient. A new HVAC system, insulation, roofing or windows could be eligible for tax credits of up to 30 percent of the cost up to $1,500.

Cancel catalog subscriptions. Shopping catalogs not only waste paper, but they tempt you to buy things you don’t really need (or want). The Environmental Protection Agency estimates that of the four million tons of junk mail we get each year, we don’t even open half of it. Websites such as cataloguechoice.org and 41pounds.org make it easy to put an end to all that unnecessary paperwork.