I wasn't sure if people would be willing to volunteer for free or not. You're more than welcome to.

The nice thing about money is that it helps the supply of listener hours expand to meet the demand, if they aren't well matched. I imagine if I had framed it as a volunteer thing, people would not be comfortable asking for money, even if being able to ask for money would have the beneficial effect of expanding supply to meet demand. So I think volunteering is fine but asking for money should be fine too.

I guess maybe I thought spending an hour a week talking to someone for an indefinite number of weeks felt like a lot to ask of a casual volunteer, but that volume of conversation also seemed like it might be pretty helpful for some people? Money helps avoid the awkward question of the point at which a volunteer's commitment ends. If the nature of a person's depression is such that they are very concerned about being burdensome, this could be important.

Edit: I heard that the biggest downside of casual listening is that the casual listener will sometimes just say "I don't feel like doing this any more", which can be tough on the depressed person. So maybe the norm should be that if you are taking money in order to help someone, you should stay committed to helping them.