The free option can charge the person least able to provide the extra effort.

Nothing priced at zero is actually free; it just moves the payment somewhere less visible. The cheaper route usually costs waiting, extra journeys, forms, phone calls, or the energy to keep asking, and those are exactly the currencies that are scarcest for people already stretched. So a service can look open to everyone while quietly sorting people by how much spare effort they have.

If you set the terms of anything, count the effort as part of the price. Ask what the slowest and most tiring path through your process requires, and whether the person on it is the one who could least afford that.