Hope you enjoy the platform!
While the platform philosophy is one identity -> one trade, you can currently use any fiat payment method (so long as another peer is also willing to use it). PayPal is by no means required, and you'll see many orders for many different payment methods! You can even make your own if one does not currently exist.
Of course, keep in mind the fiat payment stage is 24 hours, so ideally your payment method is instant and can be settled within the time limit.
Happy stacking!