There are no hard coded minimums. Some providers may demand a minimum commitment, but there's nothing to stop people in poorer regions from opening smaller channels, especially between individuals. Any business attempting to operate in the region will have to work with that.

There is also a lot of work being done on... I think they call them channel factories? Might be off on the name, but basically create as many channels as possible in as little space as possible to keep it efficient and minimize costs for individuals.