There's something I wish to buy from an internet site, but I don't wish to give them my credit card details. I have a vague recollection of some sort of temporary credit card. You buy them - I believe - from the GPO and pay into them what you will. Once the money paid into them is spent, the credit card will no longer work
Does this make sense to anyone? What are these 'credit cards' called and where do I get them from?
With the vast majority of internet sites it's perfectly safe to use a credit or debit card anyway. (I might hesitate on a dodgy-looking Chinese site but I probably wouldn't be buying from there anyway; sites like Amazon, etc are perfectly safe). PayPal gives you the extra security of having a trusted intermediary (so that your payment is to PayPal, rather than direct to the vendor) but, of course, not all vendors accept PayPal.
Well you have to trust paypal. They act as an intermediary. They take your payment details and take the money from the card that you nominate, then they pass the money and usually your address on to the website rather than you giving the website your payment details.