The sword cost just a few $, made primarily of PVC piping from your local big box. The blade is heated and flattened 3'4" schedule 40 PVC pipe. Surprisingly sturdy and pleasing end result.
Step 1: Ingredients
1" PVC grey pipe (about $1.25 for a 10' section).
1" PVC end cap (about $0.50)
1" PVC coupler (about $0.50)
1" to 3/4" reducer coupling (about $1.30)
PVC cement, PVC cleaner (found in plumbing aisle - I already had this)
PVC pipe cutters (or hacksaw or saw)
Black duct tape
Heatgun (you could also use a propane torch, but it's easy to burn/blister the PVC, and you can't sand out the brown stain. Been there, done that)
Rubber Bands (I went to my favorite big box stationer and found a bag of large red bands, and another bag o' green ones - the preferred colors of Thing One and Thing Two. Bargain).