New can get home for 3k or duplex? Help with which?

[Drake Espenlaub]

Recently got my brokers license, and have a duplex that would likely be rented to section 8, would bring in probably near 300 a unit monthly gross.  I would likely try to live in a side for a year, fixing it up and due to limited funds.  Seller asking 30k. 

Other option is a fellow from work has 2 rentals he purchased when moving to my city, one is unrented and completely trashed, with large structural issues just from going inside the house walking, and seeing the exterior. Much of the structure is likely rotted and the doorframe are actually slanted in the lower level. However location is very good, church across the street and within 3 miles of the local university.  Typically the new rent way to students here is on a per head basis usually bringing $350 per head. This home could have 3 renters. How hard is it to fix structural issues? He is hard on money now and has offered it to me at 3k, last sold for 7500 in 2014 to him, 2010 sold for $37,500.

Advice is appreciated.