You must select Friends and Family to pay otherwise a charge is incurred.  Paypal keep changing the method so you may need to look for it, but currently there appear to be two options:

On a phone or tablet:

It may look like this:

Where it says Paying for an item or service – click change
Click on sending to a friend or to family
It now selects Friends and Family

Or it may look like this:

 

 

 

 

 

 

 

On a computer:

It may look like this:

Click on “change”
Select “Sending to a friend or to family”

Or it may look like this: