Nice work. I made one myself very bodgily using an upside down drill press and a couple of mixing bowls lol it's sketchy but does the job! What sorta price you looking for?
http://www.gumtree.com.au/s-ad/beenleigh/other-sports-fitness/14lbs-urethane-bowling-ball-for-sale/1030611475
I have $50 on it on the ad but can probably go a little cheaper make an offer :) i can also resurface it for you if wanted