Why JR shows prices in dollars while some cards are in pounds, euros or riyals, and what you actually receive.
On JR, every price is shown in US dollars, because your store balance is in dollars. The card you receive is issued in the currency of its region: a UK card in pounds, a German card in euros, a Saudi card in riyals.
If you buy a UK PlayStation card worth 20 GBP, you pay its price in USD from your balance. After you redeem it, your PlayStation wallet receives 20 GBP.
Choose the value in the card's own currency that covers what you want to buy. Check the price of the game or subscription in your account currency first.
Your JR balance never expires and can be used for any card in any region.