0% Balance transfer credit cards are a great idea if you have an existing credit card, and you are paying interest each month.
Many cards on offer now will give you 0% for a specified time (typically 6 months). For example, you may have an existing credit card with an outstanding balance of around £4000. If you have it on a credit card with an APR of 14% for example, this would cost you approximatly £350 on interest over 6 months. With a card offering 0%, you would not pay any interest and therefor save yourself £360 over a 6 month period.
Some cards will also alloe you to transfer the balance from overdrafts and storecards. However it is worth considering what the interest rate will be after the introductory period.
Many of these such cards will also offer you 0% on purchases, and may also offer a reward scheme or cash back on your purchases.