Why is that at some places when you pay with a debit or credit card it only charges you a dollar at the time and then the whole amount days later? I know gas pumps do that and every now and then I will see that. Are there specific places that do that or just some? Is there a list of places that do that or does anyone know?

its called a hold, some gas stations do it and some others dont. don't know too much about it cause my bank account never goes that low

At a pump you run your card they charge it a dollar to make sure its a good card. They don't charge you the full amount because at the point the card was run you had not pumped any gas yet.

Once everything is processed they remove the dollar charge then bill you for the amount you pumped.