I have a Prime prepaid card. It only has a 'pay as u go' option but thats fine for me as i only use it occasssionaly. Its fees are about the cheapest around and it is one of the cheapest to buy. When you buy the card however it is 'disposable' and u can't reuse it till you upgrade it through their website for £1.95. I used it for car hire once and they told me that some car hire companies stop prepaid cards but it should work at most of them. However you need to ensure you have at least 20% more than the hire fee on your card which the hire company will hold as a security (called padding).
I suggest you check out the website www.idtprime.com and also moneysupermarkets comparison list http://www.moneysupermarket.com/prepaidcards/CardsResults.asp?feature=Prepaid&Type=CreditCard.
The Bank Freedom Card is Amercian - so a bit useless!
Regarding building your credit: Cashplus offer a credit builder option if you sign up to 12 months of their pay monthly scheme.
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