If you want one that you can start using with only minimal cleaning look for one that that has minimal tooth marks on the stem, and a bowl that isn't too burned out. There will be charring inside the bowl, and even some moderate cake buildup and that's ok, but the cake shouldn't be more than the thickness of a nickle. Look down inside the bowl, and make sure the hole is drilled to the bottom of the bowl. If the hole is higher than the bottom it'll always have burn issues. If the stem is dull looking, it has started to oxidize, which isn't a problem, usually a soak and a cleaning with a Magic Eraser will clean it up, but if it's heavily oxidized I'd pass on it unless you want more of a project.
Honestly, If your antique shops are anything like the ones around me you'd probably be better off picking up a new Dr. Grabow for your first pipe for an occasional smoke. They are good smokers, and the estate pipes I find are often not that much cheaper unless you are looking for one to restore.
In my world, everyone's a pony and they all eat rainbows and poop butterflies!
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