I also have PC problems i can only get online at work for the time being.
Anyway on topic for making cheap and easy poi i use these:
they are used for putting the washing detergent tablet thingys in. i usually add some more length to them and just stick a tennis ball in. They're really good for Glow/LED stuff too...
**WOW! i wonder how many glowsticks these things would hold?!?!?!**
anyway i had a look but i cannot find anything like this for the US but i get them sent out free from the interwebz, so if anyone fancys it i can order and ship them over. (or better you can come visit the UK and pick them up :P)