If you have zero experience with BBQ or fire management, a pellet grill/smoker is the way to go. I'm partial to my Camp Chef XXL Pro, which is kind of a hybrid in that you can burn wood chunks in it in addition to pellets to get better smoke flavor. (Pellet smokers are basically outdoor ovens that put a little bit of smoke flavor on the meat.)
If you're looking for something that can do everything, a Weber Kettle is cheap, dead simple and with a charcoal basket you can do low and slow cooking. Much more involved than a pellet grill, which I've run overnight while I'm asleep, doing 12-14 hour cooks.