I have the best brand of overflow that is available (LifeReef) and one that has been modified for higher flow capacity.
Here is a write-up I did about it on ReefCentral a while back: http://reefcentral.com/forums/showthread.php?t=672249&highlight=RO/DI+Dummies
I am certainly a reasonable person however (IMHO) $60 won't buy much unless someone out there has an old CPR sitting in their closet.
I could go as low as a $100 for the LifeReef, but not a penny less. Sorry