You can fill an entire wardrobe with kmart clothes for $100, it's cheaper and more practical than even op shops most of the time. Maybe just don't buy your shoes from there.
Bottle sauces and seasonings can last a long time, and can dramatically improve the diversity and quality of your home cooking. Basic chicken, rice, and greens can be turned into a dozen different dishes depending upon the sauces.
Avoid subscription services like the plague.
There's always a few exceptions, but name brands are rarely worth it.
I wouldn't be the best person to guide someone through it, unfortunately. But you can find a list of add-ons here, and there are almost certainly some quality guides by smarter folks than I to get you started.
Just in case you were being serious about the legality concern though, this may not be something you want to do.
Honestly I have stuff from clearance racks at Gap that have lasted 15 years and cost $3 -$5. Thrift stores have gotten expensive here but the mall clearance rack can still sometimes be a great deal. I didn't buy clothes this year at all, don't usually since I have enough to rotate. But when I do eventually, I look for something I can like for a long time.
Also smartwool socks, I thought I was throwing away money because they were so expensive, I got them for running because they are so good and help avoid blisters. I had to replace them last year, looked in my Amazon history and saw they were 11 years old! So I saved money really. Socks that lasted over ten years!
Of course these are all middle-income tricks. When I was very poor - you can live in your car but can't drive your house, keep the car if you have to choose. Ask for help from people you know - you would help them, right? Roommates, so many roommates. Splitting rent 8 ways makes it affordable.
If you have secure housing but not much else - our neighbor used to bring us fruit & veg he dumpster dived because he knew we were struggling. Look for free healthy food like that to supplement what you buy - some community gardens you can harvest from, that's how ours works, it's not a grow your own space, everyone grows for everyone. Some farm coops you can trade time & labor for food. We couldn't get food stamps because Florida but if you are willing to jump through the hoops that can really help get you through too.