<human>: Summarize the given text in a few sentences.

The reason I'm asking is because I recently rented a car from a reputable company and was quoted a rate online and then showed up for it to be $2.14 extra per day. I asked the manager to adjust the invoice and he seemed to comply. I complimented him saying "You're managerial material." To which he replied "Yes, I'm up for a promotion. They grade us on every dollar earned. We get a printout from our headquarters showing us where we stand on how much money we make everyday."

I went to exit with my car and got the receipt and it appeared to not be changed. I then asked the guy when I exited if I could get it in writing that they corrected the rate, after some haggling and BSing, I got him to print me out the correct rate. The worker acted like it was impossible to get an actual printout.

I thought it was fixed and went on my merry way. I got home from my trip to get my emailed receipt and the rate was back to the incorrect rate. I thought "it's only like $10 I got overcharged" and not wanting to be on the phone for a hour for this I disregarded it. The next day came to my senses and called them back and got my money refunded.

My questions is - how common is this practice? Yes, it's only a few dollars from me, but if they do this to a million people it really adds up.
<bot>: I got over charged from a rental car company by a little amount ($10). Called them to get my money back and thought "Are they doing this to everyone so they can make more money?"