Name for this concept? If a user pays once they are less adverse to further payments.
I've heard that if a user is converted from a free user of a service to paying that further payments are psychologically easier for them to accept. For example, it is easier to get a user to renew a subscription than to get her to buy the subscription in the first place.
Does this concept have a name or any source? It seems intuitive, but I'd like to link to some 'proof'.