The best way to avoid paying interest on your credit card is to pay your bills on time. Credit cards all come with an interest free period on purchases. So, if you go on a shopping spree, you won't start paying interest on your debt until about 40 to 60 days after your purchase.

Some credit cards offer interest free introductory periods on purchases as a way to entice new customers. You may get up to one year at 0% interest. But, then of course, after the introduction you will have to start paying interest. So, make sure you check out the standard interest rate too.

Interest rates vary for each card, which is a compelling reason to compare rates before you commit to one. In March 2005, the average interest rate was 16% for normal purchases, according to Datamonitor, an information company that provides industry analysis for financial services.

If you use your card to shop, then you are charged an Annual Percentage Rate (APR). Credit card companies must, by law, provide this rate in their marketing.

The differences between MasterCard and Visa credit cards are minor. They are both global, multinational companies that manage credit cards. But, they are payment systems rather than actual credit cards, so they rely on providers to use their scheme.

MasterCard recently introduced 'MasterCard SecureCode', a scheme to tackle fraud when giving your details on the internet. This service protects your MasterCard details with a code, when you buy from participating online shops.

In an attempt to reduce fraudulent card use, MasterCard, Visa and Europay agreed to introduce a chip and PIN (Personal Identification Number) system. This means that when you use your credit card, you will be asked to enter a PIN that matches the chip embedded in your card. When France introduced a similar security system, domestic fraud fell by 78%

There are specific credit cards that are only available online. What they allow you to do may differ according to the provider.

If you get a credit card from an internet bank, it can only be managed online (or over the phone). Internet banks don't have branches on your high street.

When you shop online, any pages that ask for personal information should be secured with encryption software. Encrypted pages have a padlock icon in the bottom right hand side of the screen.