Don't forget we all were extreme noobs at one time or another
I'd recommend either a good sized whole chicken (4-5 lbs or so) or a pork butt or picnic (whichever you can find. In KS, more than likely a butt, which is good)
Both can be very inexpensive and are very forgiving, easy to make and result in excellent meat and flavor. However either one is cooked at very different temperatures in your smoker. Poultry is generally cooked at higher temps to result in tight, crispy skin (I do mine at 325-350 F) than pork is. Pork shoulders are generally cooked at lower temps (I do mine at 250-275 F) and benefit from the long, slow heat.
Pick whichever one you are comfortable with and go from there.
A brisket, either small or large, is arguably the most challenging meat to learn how to cook properly, so you might want to try a couple other smokes beforehand and get a feel for your smoker and environment.
Good luck and keep us posted!