Reward Cards

If you have a Discover Card, you can earn 5% back (on up to $300, so it seems you're limited to $15 total) on gas, hotel, movie, theme park, grocery store and drug store purchases, but only if you opt in on the website or by phone.  October through December it will be restaurants, department stores and clothing stores.  I absolutely do not recommend having a credit card if you won't pay it off in full every month, because the resulting fees are very high.

Lexus Visa allows you to rack up points toward service at Lexus dealers. Amazon.com has a Visa which allows you to use points to purchase items, including Amazon.com gift cards.  There are lots of other rewards cards which are free and worth it if you can pay them off in full every month.

Now, even some debit cards are offering rewards.