Stripe should be cheaper. It's not really one or the other though, some customers prefer PayPal so you might want to offer PayPal for those customers, otherwise default to Stripe/card.
It might be worth starting with both and seeing what your customers actually use. I've found UK customers are very much happy to pay via card, so I stopped offering PayPal in the UK and received no complaints or drop in sales. However in the USA where the banking system is worse and a lot more people use PayPal, I continue to offer PayPal... for now.