I am an employee at McDonald's and twice they have asked me to drive out to another store, using my own car, to get them stuff such as cups and tray liners, and since gas isn't cheap, will they pay for the gas I spent driving for them?

Ask the manager.

They should but they probably won't. You should get about 50 cents per mile. If that started happening to me I would start parking a block from work.

You should ask. The IRS considers business use of a car to cost you 56cents a mile.

An employee can't really deduct the mileage on their tax return because the first 2% of your income doesn't count and after that you have to be able to iteimze.

no, but you can deduct it from your taxes

No.