Dear Rhosyn,
Please be careful with credit cards. They can really be bad things if you do not use them correctly. When interest kicks in it makes it very very hard to pay off. And they are not merciful when you are even a second late in paying them.
For your first query I would think that if you were disciplined to just use it for your petrol expenses for work and to pay it off every month, in full, without fail then you are on to a clever way of earning yourself extra tesco points and releiving you of that extra expense.If you default by one late payment your 0% will no longer be valid. This happend to me with Virgin and your talking to a machine with these credit cards. I was honestly one hour too late via internet banking system in getting the money to them on time! My 10 months 0% was GONE! If you pay the minimum on time your 0% will be intact. As you are getting expenses to pay for that petrol then make sure that it does pay it in full. Dont have money hanging about on the balance if you can help it.
Your second query, again, proceed with extreme caution and do not be tempted by the money that gets thrown at you. Use them wisely and to your advantage not to thiers.
I stupidly got two cards for those just in case times and although the debt is small it looks like I will have to pay for the next 20 odd years if I only paid minimum payment!
I pay £25 per month for £480.00 Each month I am charged £15 on to my account. If I am late they charge me £12.
Like I said before the first idea sounds fine if used wisely. I would do my best to save for the second. Who knows those tesco points may even help you save money...who knows what the future will bring in 2010. You may have built up such a great reputation with paying off the petrol credit card every month in full that you will get better financial deals by 2010.
I hope this helps you. You will know yourself better as to how well you would manage these cards.