It's hard to describe how much I sympathize with you. I once had a flat tire when abysmally broke. I ran into this from time to time, as my method of replacing tires that went flat was to go to places that replaced tires and asking if I could have one of the ones they were throwing away. They usually had a dumpster full of tires I was allowed to pick through to find one that had no obvious leaks, and had the right little numbers on the side, like 'THX-1138', that let you know it was the right size to replace the one that had failed.
This happened on the side of a busy highway, and I had no spare, nor even the $10 to remove the old tire from the rim. I wandered around like the Israelites in the desert until some tire guy was moved by my plight, and let me scrounge a tire from their dumpster, at which point I rolled it back to the promised land.
Not having the $10 was a problem, as tires need to be full of air to do much good, and bolted to the car, as well. A couple questions to the tire guy revealed that with a crowbar and large hammer, it was possible to 'break the bead' which sealed the tire to the rim (the part that bolts to the car), and then using the crowbar, one can pry the rubber off the rim.
Sounds easy!
Welp, it's not. I learned lotsa stuff, such as that TWO crowbars are really necessary (but a big, big screwdriver can stand in for one of them), and the biggest hammer you can swing is the hammer that is big enough to bust the tire loose. It's also easier to chop a cord of wood than it is to break down one tire. so the next time you spend $10 to swap a tire on a rim, thank capitalism for getting folks to invent tire machines that do in a few minutes what used to take three hours of backbreaking labor.
Once the old tire is off, you beat and pry the new tire in place. Then, you need an air compressor to fill it, and as I seemed to have misplaced mine, back to the tire guy - who had one, for sure - I rolled the unlikely assemblage of rubber and steel.
Good thing air is free!
Eventually, the tire was full of air, bolted to the car, and I was ready to roll!
Good times =)
Moral of the story: If you don't have $10 to pay for the tire machine guy to swap your tire, sell enough kidneys until you do, and, remember to keep a spare tire on hand, like you do kidneys. If you have a spare couple bucks someday, it might be smart to install a couple extra kidneys to have on hand should you ever run out of spare tires.