I know some folks love power grips and I've seen them in a few races - perhaps a medium between cages and clipless?
http://powergrips.mrpbike.com/index.php?section=index
Pyro Platforms: These won't save much $ (or any depending) once you add cleats, but they sure do intrigue me. If anyone ever uses them I would love to hear about your experience!
http://www.tri-zone.com/Details.html?cat=69&item=PYPLT