rbjh:the 16.2% purchase rate is on the cost of a purchase correct? so on £100 i will be charged £16.20? My question is if I pay off the card in full before then end of the month do I still have to pay interest?
No. On credit cards the interest is usually quoted for a year so there would be £16 interest charged if you owed £100 for a year. However, you should not spend anything on a credit card unless you are fairly certain that you will be able to repay the debt in a month or so. Usually (but not with all cards) you will not be charged any interest if you repay the balance in full every month.
There are small differences between cards so you should read the small print and, when you get the card, make a few small purchases to see how things work. It's usually possible to just repay a small amount each month but, if you do this each and every month, then your debts will mount up quicker than you might think.
Most cards will let you choose the statement date and it is usually convenient to ask for this date to be a few days after pay day if you are paid a monthly salary.