My dad travels a lot for work (he’s a advisor for a hospital consulting business), so he’s learned a thing or two about getting the best deal when he travels on his own dime.

Take renting a car. All the rental car companies have Web sites these days, and you can use them to compare rates. If you don’t have a discount code for the companies that have the three best rates for the dates you need to rent a car, scour the Internet. There are lots of sites that make discount codes available,

Hint: For the absolute best rate, time your trip so you avoid the most popular times of the year for your destination. For example, skip San Diego in the summer time … that’s when everybody wants to go. Try for March or October, when the kids are back in school. When there’s less demand for rooms and rental cars, you’ll get the best bargain.

Day of the week matters, too. Some places, mostly business destinations, are a comparative ghost town on weekends. If you’re traveling to cities like Boston, you can often get better rates on the weekend. For example, with an Alamo weekend rental, you can save over $20 a day. You can play the weekend angle with hotels that cater to business customers, too.

Here’s another hint: are you a member of Costco? Sam’s Club? What credit cards do you have? Check your memberships and credit cards to see if they offer special discounts on car rentals. But remember, you have to use the credit card when you make the reservation.