http://cgi.ebay.com/ebaymotors/PHOTOSHIELD-LICENSE-PLATE-CAMERA-PHOTO-SHIELD-COVER-NOW_W0QQcmdZViewItemQQcategoryZ50434QQitemZ8030014 014QQrdZ1QQsspagenameZWD1V
Don't know if this is cheaper than where you're finding it online or not.
I saw a TV report on it by our local TV station and the lenses do work and work much better at night. That spray works, but it according to the TV station, it has to be reapplied and doesn't last forever as it's advertised.
Just don't run yellow-to-pink lights and you'll be fine!