I bought some a few weeks ago at "The Walking Store" here in our local mall. Cost me $60, and they work GREAT in my bowling shoes. I've tried the more expensive ones, and they don't work as well.
One caution, though - I once tried the 3/4 length ones in my bowling shoes, and ended up injuring the ball of my foot, because of sliding back and forth over the end of the insert. I now have full length ones in the bowling shoes.
Another suggestion - how about moving them from your street shoes to your bowling shoes, and back again???