If you live in a city and you're not born into wealth, everything for miles around you is owned by other people: Likely some
40% of it by one-hundredth of the population and
93% of it by the top one-fifth.
Private property is a (good and necessary) restriction of other folks' freedom, by definition: You are not allowed to walk, sleep or grow food on property which other people own. And when virtually everything around you is owned by other people, you have absolutely no way of supporting yourself through your own personal efforts. Maybe you could gather your resources and take a week-long hike out to the wilderness, to live off the land. But it's impossible for 300 million people to do that; that would be a 'solution' for only a tiny percent of people, even if everyone wanted to do it.
So overwhelmingly, the only option is to remain in society and surviving by transferring ownership of clothes to wear, places to sleep, food to eat and so on from other people to yourself. The only legal/ethical way of doing that is by
buying them. You're not forced to buy from any one particular provider, but whatever you can't personally produce for yourself (which is basically everything, if you're in the bottom 80%) you
do have to buy.