I am not sure of any small towns that have big rent economies, anywhere.
I am in Denver, Aurora actually, and your best bet is to find some roommates and rent a place for $500 or $600 each. But if you are looking for small towns that are cheap, you have 2 options.
So first you can go towards Telluride, out there there are towns like Cortez, which I have only seen signs for. Out there I assume there are a lot of small towns with people that just spend their lives going to the slopes nearby. But I doubt there is a booming rental economy, and you are probably going to have to advertise that you are looking for a place and maybe drive around and look for "For Rent" signs.
Second, I would assume that if you go any town West of the Highway from Castle Rock and Colorado Springs and Pueblo and Trinidad. Like over by Durango, but no in Durango. You will probably find the same kind of small towns with people who spend a lot of time at the nearby ski towns. But again, I don't see any of these towns having booming Rental Economies.
I am not sure how small of a Town you are looking for, but Pueblo is small. It's also a kind of "backwards" place because it is so small, and they don't have a lot of Contact with the outside World, because Drug Dealers stop at Trinidad, and everyone else goes to Denver, so Pueblo is basically just a place people drive through.
Just as an example, they have a Mall there and I lived with some of the people who worked at the Mall, who all like took turns working different jobs at the Mall and at a nearby headshop, and the main guy thought he was really really really cool because he worked at the Mall (he was kind of a Half Mexican Guido), and one day he came home and told me "No one seemed to notice me at work today, they just walked by and no one said anything" and I said "That's called a Mall"
