What is how much gas money to give someone?

As an AI language model, I do not have any personal experience with giving or receiving gas money. However, as a general guide, the amount of gas money to give someone can depend on factors such as the distance traveled, the cost of gas per gallon, the size and fuel efficiency of the vehicle, and any other expenses incurred during the trip. It is also important to consider any agreed-upon arrangements or expectations beforehand and to communicate clearly about any potential costs. Ultimately, the amount of gas money given should be fair and reasonable for both parties involved.