I've done Amy's center pull yarnball rolling technique with great success - and they were just that - a ball! Perfect for most things.
BUT I needed flat-sitting balls so I can place four on a lazy susan turntable (that I am going to turn with my toe!!!) which will enable me to finish shoulders of a sweater I'm knitting in the round without having to end up knitting flat. I went to THREE LYS's looking for a ball winder - no luck. Didn't have time to wait for on-line shipping.
SO>>>I took an empty toilet paper roll, and to make it more professional looking, I used a real hole puncher to punch hole near top. I threaded the yarn in from outside to the inside. Then folded the toiletpaper roll in half lengthwise. Wrap the yarn around and few times and proceed with Amy's instructions. When big enough for your purposes, cut yarn and end. Then grab your pull from the hole at top and then gently remove the toiletpaper roll for future use.
VOILA - perfect flat-sitting yarn balls. AND I saved $39 and tax and shipping.
Now what do you say to that????? (Buy more yarn....