Till a few years ago air in bicycle tyres was filled with pumps operated manually. Those pumps were available with the cycle repair shops and were free to use. Now a lot of tyre repair shops have an attachment that can be used to fill air in bicycle tyres as well using a compressor.
“Hey can I use this to fill air in my bicycle?”
“Yes sure, it will be two bucks.”
“Oh! OK.” And thinks to himself to get the full value for his two bucks.
“I think this much of air is enough.”
“No I think it needs a little more.” and thinks about the two bucks he is paying
“OK. Suit yourself”
The tyre can't handle so much of pressure and explodes
“It will be ten bucks to fix that puncture. May I?”