Valve have explained why PayPal is currently unavailable as a Steam payment option in a number of countries around the world.

Click your account name in the top-right corner of the window. Click Redeem a Steam Gift Card or Wallet Code in the small menu on the right side of the window. Just type in the code from your gift card or wallet code and see the money appear in your Steam account.

Millions of Steam users worldwide can no longer use PayPal for purchases in most currencies, leaving affected regions to rely on alternative methods or Steam Wallet codes. Valve cites a bank decision behind the disruption but gives no clear timeline for restoring support,