Definitely get a Realtor, as the others advise.
As I understand it, a lot of property in Detroit is virtually worthless. So prices can be very low.
A couple of quick observations:
If you rent, make sure the property isn't in foreclosure, and isn't heading there. Otherwise, you could find yourself homeless in a few months.
If you buy, do it right. Make sure there's a good title search, and that you buy title insurance. You want to make sure there aren't any liens or judgments attached to the property.
As for whether there will be a down payment: If you buy conventionally, the lender would require one. (Unless you're doing a VA loan, or some other program that doesn't require a down payment.)
If you're dealing with owner financing (or something else, such as a lease-option), that's fully negotiable. The seller would prefer a down payment. You'd be better off with as small a one as possible--or none. Again, though, that's negotiable.
So, go and get a Realtor. Make sure it's one with some experience and one who understands creative financing.
Hope that helps.