My practice poi consist of 2 skeins of yarn and 1 craft cord, takes about 10 minutes to assemble, and is very affordable.
The title pic is a beautiful shot of Nick Woolsey's fire poi.
For more on poi, check out www.playpoi.com.
Step 1: Ingredients
1 10 yard craft cord (available at any craft store)
2 2 oz circular skeins of cotton yarn (available at any craft store)
Step 2: Wrap the Cord Around the Yarn
2. Stick your finger thru the center of the ball of yarn, then stick the cord through.
3. Tie a knot in the cord, then slowly, tightly, and evenly wrap the cord around the yarn over and over, until it covers the yarn like the picture.
4. Leave at least 3 feet of cord at the end (in this example, there was easily 6 feet left over).
5. Tie a knot at the end of the cord, wrapping the cord around the yarn.
Step 3: Make Handles
7. Tie 2 loops at the end of cord in your hand.
8. Put your index and middle finger each into a loop, and re-measure.
If it is too long, you can loop the cord thru the yarn, and tie more knots.
If it is too short, take out the loops and try again.
Step 4: Rinse, Lather, Repeat, and Even It Out.
The toughest part of this whole thing is making sure both poi are of the same length.