Periodically, I identify credit cards with excellent rewards. Fortunately, there is a great deal of competition in the credit card market. As long as you pay your balance in full either at the end of each month or at the end of special offers, you can receive substantial rewards.

Here are a few of the best rewards cards for your consideration.

Discover it Cash

This card offers excellent rewards for one year. There is no annual fee. If you apply now, Discover will double the rewards you earn at the end of one year from the time you receive the card. Each quarter, there are several categories in which you receive 5 percent back on purchases. For the present quarter ending Dec. 31, you earn 5 percent back (which will be doubled at the end of the first year) on purchases at Amazon, major department stores and Sam's Club (with a few restrictions).

All purchases other than those earning 5 percent earn a 1 percent reward. So, under the current offer, at the end of one year new cardholders will have received a 10 percent reward for the purchases highlighted each quarter, and 2 percent for all other purchases. The rewards are limited to $1,500 of purchases each quarter or $6,000 per year. If you limited your purchases to the 5 percent categories only, your rewards could be as much as $600 for the year.

There are two other excellent features. For the first year, there is a zero percent APR for new purchases. If you pay your balance in full at the end of a year, there are no interest charges. Interest charges are variable, based on your credit background. Currently, the lowest rate is 11.24 percent; the highest is 23.24 percent. After you are approved, Discover will inform you what your rate is.

The other excellent feature is an 18-month balance transfer feature with no interest charge. As long as you repay that balance by the end of 18 months, there is no interest charge. Any balance outstanding at the end of 18 months is subject to interest charges.

Blue Cash Preferred

by American Express

This card has a $95 annual fee. However, there are features that will allow you to recover that fee.

For the first $6,000 you spend on groceries, you receive a 6 percent reward. That results in a $360 reward, or $265 net of the $95 annual fee. There is a limited time offer of a 10 percent reward for Amazon purchases within the first six months (limit $200 cash back). Rewards for gas are 3 percent, for major department stores 3 percent, and for other purchases 1 percent.

The best strategy would be to restrict your purchases on this card for groceries and Amazon up to $6,000.

There is a $150 cash introductory bonus if you spend $1,000 on the card in the first three months. The bottom line is that, for new cardholders, the total rewards would be $510 for purchasing $6,000 in groceries and qualifying for the introductory bonus, well worth the $95 annual fee.

Citi Double Cash

I have recommended this MasterCard in a previous column. There is no annual fee. You receive a 2 percent reward regardless of the type of purchase. You receive a 1 percent rebate when you make your purchase, and 1 percent when you make your payment. There is no restriction regarding the amount of your purchases each year. You do not have to be concerned about different categories that change each quarter.

Elliot Raphaelson welcomes your questions and comments at raphelliot@gmail.com.