look at West Marine or Boaters World (store or online), or Overtons. There are several varieties and they are very easy to install; probably just need a screwdriver.
This is the one boater's world sells for $50. I bought mine from this seller. I haven't put it on my boat yet so can't comment on effectiveness, but this was the one most recommended by others in my/our position (I/O).
I bought a foil from Overtons I think is a stingray WOW what a differance on plane speed and with white wash the biggest advantage for ridding white wash is BALLAST LOTS OF BALLAST a four blade prop will help plane faster as well