Actually, I was thinking of options for a lower-magic world. In that sort of world, even a 1st level character spreading around his small handful of healing spells can be surprisingly effective - and therefore command a lot of respect.
I dont think it makes game-sense to have a character be able to build a temple until they reach 5-7th (or even higher!) levels; I was mostly curious how to play out the growing respect and influence that the Clerics power can bring him. As word gets around that the Cleric is willing to heal or to give alms to anyone in need, what sort of events do people see happening?
For now, every day that goes by that the Cleric leads a service and then does charity work I am increasing the number of people who come to the shrine; either curious or needy or actually interested in Illmater's message.
But pretty soon, all sorts of interesting things can happen. Established temples in the city may see this crusading Cleric as a rival; people may be so moved by his piety that they volunteer as lay-workers; someone might attempt to buy the services of the Cleric for themselves.
But I am not so much looking for adventure hooks as more of an economic/political sort of thing: how much could you collect in donations if you gave away your healing instead of selling it? How many new followers would come to your church, and how many of them would be serious believers as opposed to trying to grift off your generosity? Basically, how does a church grow from scratch?