Travel can be costly, but if you know what you're doing you can cut down on your costs. It just takes a bit of effort.
The writer of The Perpetual Traveler blog, Glenn Campbell, ran into some unexpected expenses when he arrived at Ontario airport too late to miss his flight. This meant that he wouldn't be able to get a flight out until the next day...and also meant that he'd have to find a place to stay. He had only been to Ontario Airport once before, but he surmised (correctly) that he wouldn't be able to sleep at the airport itself. But as he approached the airport to turn in his rental car, he hit upon a solution:
I had no real worry that I would find a place to camp. I knew that the airport was in a relatively sterile industrial area, away from any housing and probably without any homeless population. The aerial photos showed lots of open land and landscaping where I could easily hide. I could resolve exactly where after I dropped the car.
Campbell had a sleeping bag, but it didn't seem to be suitable for outdoor camping, so he bought a second one for $15. He dropped off his supplies in a field before turning in the rental car, then returned to the field afterwards.
More here.