In a capitalist society, your power to express yourself and effect change is tied very directly to your purchasing power. This means that if you want to make a difference in the world, you have to put your money where your mouth is, someone's quite literally.

Food

Look for sustainably sourced products in your grocery store, and seek out local produce where you can to have an immediate impact on your carbon footprint and also get better, fresher food. Try finding farm-to-table restaurants, or encourage local favorites to buy local or sustainable ingredients. If you're worried about costs, remember that there are often ways to try a product at a discount. You can get sustainable coffee beans on sale or a high impact whey protein coupon to try out new products that are better for the environment.

Clothes

The clothing industry does more than its fair share of damage, not just to the environment through manufacture and shipping, and to customers through toxic processes, but also to society at large through slave labor and sweatshops. If you want to reduce this impact, pay attention to where your clothes come from and try to reduce your consumption by repairing the clothes you have and buying second hand wherever possible. These days, you can even get luxury brand names in excellent condition from second hand consignment shops.

Household Goods

Beyond food and clothes are the everyday supplies that keep your house in order and operational. Things like paper towels, toilet paper, storage bins and shopping bags can all be bought from eco-friendly or sustainable suppliers. Also pay attention to plastic, because many of your most commonly bought home supplies are either made of plastic or come in plastic containers that should be recycled if at all possible.

Cleaning Supplies

Cleaning supplies are among the list of products that commonly come in plastic containers, but on top of that, the cleaners themselves can have an extremely negative effect on the environment. Many chemicals that you use to keep your home clean and safe can be harmful if they get into the water table and contaminate your local aquifer. Water pollution is particularly difficult to deal with because of the way it is constantly in motion. The pollution from your town probably won't be really felt until it's at least a few miles downstream, or even all the way to the nearest ocean. Once it's in the ocean, it can end up anywhere in the world.

Personal Care

The same pretexts that apply to cleaning supplies and household goods apply to personal care items. What is in your personal care items and how does it break down, or more likely, fail to break down, once it's in your system or going down the drain? How was it tested? What kind of packaging does it come in and what do you do with that packaging when you're done with it?

Tech

Last and perhaps most difficult is the area of technology. E-waste is an ever-expanding problem in our world, the source of tons of toxic waste that's almost impossible to efficiently recycle, so for starters it's best to do all you can to make your technology last longer. Use your service contracts instead of simply replacing, and ask what your tech suppliers are doing to make their products more eco-friendly.

This isn't to say that purchasing power is the only power you have in a society like ours. You can vote, make environmentally friendly life choices and even raise awareness. If the safety of the planet is an issue that matters to you, there are countless ways that you can help and one of them is through your purchasing decisions. Whatever you can do, you absolutely should do.