um, it really depends. You could buy one for as cheap as 8 bucks or so. But, i'd get a nicer one then that.
Depends on what you get. Nice glass piece prob be around 30 bucks. You can get one for cheaper though. All depends on what you want.
a spoon is about 20-50 dollars depending on quality... not too family with bong, bubbler, etc. prices
From what I've seen you can get very cheaply made asian pieces for around $6-8, or you can go someplace nice and get a quality pipe for $25-30. If you want something REALLY fancy (which I don't think you do) you can find a pipe for as much as you're willing to spend, but I couldn't justify myself spending more than $30. I just bought a new pipe that was made by a company called Oregon Glass, and I love it! I should post some pics soon, it's so sexy.
I got my metal/wood one for 10 and my nice glass one for 35 so it's all depending on how much you have to spend.
Look at online stores as a general guide, but it differs widely as for regional headshops. I carved my own pipe out of fresh cedar and since cedar doesnt burn well, i dont have to put any chemicals on it.