I do not have a Monzo bank account and currently don’t want to upgrade to one and am happy to keep using My Monzo card as a prepaid card, which contributed to the following annoyance:-
I registered my card with PayPal.
I transferred some money from it to my wife’s PayPal account
I had to pay £3.50 transaction fee.
Contacted PayPal who refunded me the fee.
Sent a screenshot of my statement on request from PayPal
PayPal has turned My Monzo card to a debit card with zero fees.
Although everyone’s case may differ I hope this post will offer some comfort in knowing that you can pay for things without paying fees through PayPal.