A broom handle or solid wood dowel. Length is up to you, but it will likely fall between 3.5 and 5 feet. Check out this thread
for a discussion of contact staff length. (Summary--your contact staff will probably be longer and heavier than your regular staff.)
Old bicycle tubes - I used 4 road tubes and 1 mountain tube. You could experiment to find the weight that works best for you. My staff is pretty heavy but I find that keeps it slow and helps me learn the moves.
Bike handlebar tape and electrical tape
Flat head thumbtacks