Cinni is a new drug that can be found in Saints Rows 3. It is sold by the 6th Ave. Sinners and in Drug Trafficking activities. You can sell it after beating "New Drug in Town" Sinners Mission. It can be sold for $200- $400. It's basicly cinnimon sticks grounded and mixed with a few ingredents in cigarettes.
To obtain Cinni, go to one of your cribs and acess Drug Trafficking. The instructions are to find Sinner Vans that sell Cinni. After damaging a van, boxes will fall out. Putting the boxes in your vehicle will rise your Sinner Notoriety to 2, so drive to your crib and drive fast.
To sell Cinni, get in the marked car that contains the Cinni. After you get in the vehicle, there will be many markers to choose from all over the city. Go to your map and set a waypoint for one of the markers. when you reach your destination, go up to the markered guy and press 'Y'. Then go to your next costumer until you are all out of Cinni or until you meet your deal limit.