50% ownership for sale, co-owner staying in property

[Eric Doerr]

I came across a property that I'm interested in, but ONLY the owner's 50% interest is for sale and the co-owner is not selling his/her interest and is residing in the property.

How does this work?  Could I charge the co-owner, who is staying in the property, rent for the half that I would be buying? My hope would be to be able to eventually buy out the co-owner and flip the property or keep it as a rental.

It's in a great, high income area that is growing rapidly.  It's near great schools, plenty of jobs, and public transport. The half that is for sale is being sold for nearly $30K less than what half of market value is for the entire property so I'm very interested.

I'm a rookie.  

Has anyone ever come across this before?