Ownership can be a burden. Once you buy something, you have to carry it around, fix it, remember where you put it, and keep it clean. "He who owns little is little owned" (Henry David Thoreau)
How to stop buying and reduce your ecological footprint on the planet?
It's actually not difficult!
Practice reverse snobbery. Express contempt for people who mindlessly buy things. This has two benefits: It raises the act of not buying things to a lofty moral height, from which you can denigrate others, and you get to enjoy the irony of simultaneously being a snob while making fun of other snobs.
Go to shopping malls and department stores and briefly let your materialistic impulses loose. Try on a bunch of sweaters and choose three or four. Add a few ties or scarves. Walk around for a few minutes enjoying your stack of loot. Then put it back on the shelf and walk out. Think about how unnecessary that stuff is. You probably already have something just like it. What a relief to not have more junk around the house.
Get satisfaction from money saved, not money spent. You will be able to work less and still live comfortably.
Become a scrounger. Old bicycles, furniture, building materials, vehicles, books and clothing are everywhere, once you start looking. Become skilled at resurrecting old stuff and finding uses for it. Take pride in being an eccentric recycler.
Look for barter opportunities. Swap.
Consider having a "buy nothing Christmas" this year. You can find details at BuyNothingChristmas.org.