Welcome to the forum!
Since you are specifically talking about pulled pork, you need a smoker that can run for 12-18 hrs. with little to no input from you at a steady temp. It sounds like you probably are looking at either charcoal or a wood burner. Wood burners are nice, but generally start at about $1000-1500 and go up from there for a good one. Charcoal has more price points:
- ECB (El Cheapo Brinkman) - small vertical smoker, can be modified to produce some good smokes and can buy one used for about $20-$40
- Horizontal offset smokers (Char-griller, Charbroil) larger smoke chambers, fire box is off to the side, generally require a lot more input from the user to maintain temps over long smokes, used they run about $100, new $200.
- Weber Smokey Mountain: comes in the 18.5" and 22.5" size, are what I call "smoking for dummies" easy to use (which is why I have one ), when set up and running can run 18-20+ hrs. on one fill of the charcoal ring depending on weather. You won't find many used because they last forever and people tend to keep them, new the 18.5" can be picked up between $250-$300, and the 22.5" for $350-$400.
- Komoda/Big Green Egg's - super efficient, run forever on a small amount of fuel, are incredibly heavy (so make sure you get one with wheels on it), don't see very many used ones as they also last a long time and are generally held onto. New they are kind of spendy, start around $1000-$1200 and go up from there.
Take some time to poke around on the forum, sign up for the 5 day e-course for free, read up on the various types of smokers and how people like them. Don't be afraid to ask questions, and once you make your decision holler and we will get you plenty of tips on how to turn out some stellar pulled pork!