I don’t know if it works out dearer but I’ve bought Adultwork credits in the past using my PAYG punting phone
Register it to your AW account ( this won’t trace you as it’s unregistered PAYG ) then put credit on it. You can then ring a number where you get so many credits per £
I can’t remember the amount of credit per £ - sorry.
Unless you're putting very large amounts of credit on at a time this is a very expensive way of doing it for instance on a £5 top-up is almost twice as expensive as using a card.
As has been said the easiest way to do it is to use a Paysafe card where you can use that in two different ways the simplest is where you just go and buy a predetermined value top-up voucher and then use it on AW in the same way that you used to go and use a voucher to top up your pay as you go phone for those of you old enough to remember that.
But there is also the option to create a Paysafe card account and then top that up with your vouchers and then pay AW with that. The bonus of that is that if you're interested in gaining Freeview credits it a lot easier to make a £30 AW top-up [ which gives you 3 free views ] than it is directly crediting the vouchers where there isn't a £30 voucher value option. There is a way around that but that's where it starts to get complicated.
Two other things to consider
People are often concerned that if there's an issue can they get their money back if there's a problem using the voucher well my advice is that its a lot easier to do that at say Tesco Express than it is at some backstreet convenience shop [but always take the till receipt as well as your vouchers as that gives you legal rights and means that the shop is much less likely to argue with you and just do a simple refund ] the downside on a Tesco Paysafe voucher is that the 16 digit number is printed in very small typeface and can be very difficult to read for anyone whos sight isn't brilliant whereas the typeface on the voucher that you get from the PayPoint machines in smaller independent outlets is a lot larger and easier to read.
If you're considering creating a Paysafe account be aware that if you have tight security on your device it may not allow you to access their website as it appears there's something in there that the protection sites like AVG don't like and won't allow your device to connect to or display it. It's well established that the site isn't actually insecure and likely to be hacked but just that there's something in it that their systems don't like. Paysafe has been saying for months that they are in the process of sorting it out but don't seem to be getting anywhere with it.