[mattdub]

If it's for credit building I suspect it's due to a low score.

I would suggest a CapitalOne card and then put your fuel on it only, pay it off every month and then if you feel you can trust yourself then put more expenditure on it.

But pay it off in full. No exceptions

Seconded, i did pretty much exactly this with a halifax card (money saving expert highly reccomended for this purpose) The amount doesnt matter, you could buy a magazine/pack of ****/hairbo tangfastics every month and aslong as you pay it off and do this for a certain period your credit score will increase.
Worked fairly well for me...Other way (if it ties in with a big purchase) is to buy something of x amount and then pay off as much as you can per month within the interest free period and then do a balance transfer onto another card that also has an intereste free period until youve paid off what you owe.
Got to be really savvy with the second option though, its just sometimes it can be advantageous.