Chicken Thighs and pork butts are cheap...
As mentioned above, pork butts are very forgiving when smoking. I would suggest cooking a pork butt or boston butt roast. This cut of meat has a lot of fat and takes a while to cook, so it is very forgiving to most beginner's mistakes. Purchase a pork butt, usually about an 8 pound average with bone in. Some stores now only sell boneless pork butts which will work as well. Just make sure that if you have the boneless pork butt it is rolled and tied properly.
In most cases there is no need to trim excess fat from the meat as most of the fat is going to render away. For the beginner I would not recommend trimming the meat until he / she cooks a few pork butts and sees how the fat renders down. Once you understand how the fat cap renders down, then you may trim the fat if so desired.
Liberally apply a coating of your desired rub, cover, and refrigerate overnight. About 1 hour before smoking remove the meat from the refrigerator let sit uncovered for about 30 minutes while you ready your smoker.
You can also cut the butt into a couple pieces and season them differently to compare the final taste results.
