An important distinction to make when discussing this topic is the vast different between DOMESTIC (same currency) money transfers and INTERNATIONAL (different currency) money transfers. The ease and expense of international transactions can change drastically based on the regulatory, anti-money-laundering and reporting requirements of individual countries, and whether it is a family/friend transaction or a business transaction. There doesn't seem to be a one-size-fits all approach, and as with everything in the permaculture: "It depends..."
Paypal, for instance, might be free to transfer money between two Paypal users in the same country (because all they're doing is adding/subtracting from their own internal computer system). If I wanted to send money from Canada to the US, however, Paypal becomes one of the MOST EXPENSIVE options (4% exchange margin + C$2.99 fixed fee + 2.9% if you use a credit/debit card.) [Source:
https://transumo.com/paypal-international-fees/ ] Fees may increase/decrease based on the amount of money being sent and the currency it is being exchanged for.
Wise.com uses a clever trick to keep international transfer costs low. Imagine someone across the country owes you $5, let's call them Eskell. Your housemate Marsha, also happens to owe Eskell $5. Instead of Marsha sending $5 ALL the way across the country to Eskell, and then Eskell sending $5 ALL the way back to you, Marsha walks up to you, slaps a fiver in your hand and everyone is made whole. Much simpler and more efficient.
Initially I was turned off to Wise.com due to the huge number of negative user reviews, but as I dug deeper into more reputable sources they've had nothing but good things to say (Monito.com gives them a 9.5/10 rating; trustpilot.com rates them 4.6/5; reviewopedia.com writes they are "both safe and convenient.") All those short, similar sounding "negative" user reviews start to smell more like an astroturfing campaign by one of their competitors (i.e. the big banks) to scare people away. [this is %100 speculation and wise.com could still be a huge scam, or at least a very unpleasant experience for some people, so proceed at your own risk.]
When I was making my wise.com account, they asked me for my "occupation", which I felt was a little strange and unusual. But it turns out they need to have that information to remain in compliance with Canadian regulations (all explained transparently on their website). If you sign up from a different country you might not have to answer that question, or you might have to answer a set of different questions.
Just thought I'd share my own limited research/experience so far.