First, buy a can of Pringles (in the U.S. Pringles is a preformed potato chip).  Throw away the chips if you expect them to taste like potato chips. 

Print out the nose cone, nose cone parachute lug, fins, and the motor can pieces. Use supports on the motor can. If you use a Prusa, just add supports to the outside of the can from the base to the first level. In any case, the motor can needs supports. CA glue the nose cone lug to the bottom of the nose cone. I also put a hole in the nose cone to add weight for better balance. I added about 30 grams total (including hot glue). If you wish, paint the Pringles can. Scrape off the region where the fins fit on and CA them to the body.

Glue the top motor can piece to the top of the motor can.  If you feel lucky, glue the motor can into the Pringles tube (after you paint it if you want to paint it). 

I used PLA for the fins and nose cone and PETg for the motor can pieces. This make makes use of nose cone libraries but you can also use preformed nose cones. 

This uses a 24mm D motor (D12-5). I tried it with a C and the rocket was too heavy for it.  However, it is very enjoyable with a D motor.