Good topic.
Here are a few:
Clothes:
Learn how to sew for repairs. With a needle and thread you can repair nearly any article of clothing you have. I usually always keep some glover’s needles and artificial sinew or nylon thread around for this.
Learn how to sew to make your own clothing. Instead of buying a new article of clothing, buy fabric and use patterns to sew your own clothes. Often I find that this way you get a much more useful and practical parka or mukluks or canoe packs, etc , because you choose how big it is or what straps to use or what material to make it out of. I have sewed pants before but those are more tricky to get a good fit so I don’t make much of them anymore. It’s nice to make your own things anyways and tailor your clothes to your needs.
Buy what clothing you need at thrift stores.
Tan your own hides to obtain leather or ask a tannery for scrap leather they don’t need to make bags, clothing, etc. Many throw out lots of leather and it can be obtained for free.
Food: Herd your own goats, keep your own chickens, grow your own vegetables, shoot your own deer, snare your own hares, etc. Get leather, milk, meat and goat hair from your goats, eggs and meat from chickens, buckskin from deer, etc. Think towards producing food yourself, rather than going to buy it at the shop. Working at a place that serves food can probably also help out with food costs. Some people find dumpster diving good but I don’t do it much because most of the food I’ve found in dumpsters hasn’t been that edible or healthy.
Obviously if you know a community or group of people who can help with food production and that you can contribute to, that helps immensely compared to doing it on your own.
Rent: Having a place in the country to squat or live on is the most economical option, as you can also produce your food there. Yet in winter this isn’t always possible if you don’t own the land or it’s too far north, etc. Otherwise, make friends with people in order to squat in their homes, their land or their buildings. There is work exchange you can do for a place to stay, and often farmers or ranchers will hire someone and provide room and board as well.
If it’s not winter (or not freezing and snowing) buy a tent and camp out in that in summer, spring, and fall. That is what I do when I am in Canada and can obtain a cheap tent. Otherwise I sleep with a blanket/mosquito net or whatever I have out in the open and if it starts to rain head for some kind of overhead shelter.