How freely do you want the prop to move? We used PVC pipe connected with those U-shaped elbow joints on our "witch stirring cauldron" prop. If you don't glue the joints, they can be moved and posed - go for a slightly snug fit at the pipe/joint connection. We used something like eye bolts at the shoulders so the arms could move freely.
"Life is pleasant. Death is peaceful. It's the transition that's troublesome." (Isaac Asimov)