Buying a Polar S720
Polar S720 on ebay. Hoops has been on me to get him a new bike computer. The S720 is about $330 from excelsports.com, so I've also been looking on ebay. The query above is one way to find it. You have to subtract out items because folks list the S720 as S-720, S 720 and 720 which are queries that you can't run a one liner on ebay.
Anyway, this shows that the lowest price has been about $212-232 for this, so it is quite a savings from the "$300":http://www.coloradocyclist.com/common/products/productdisplay2_v2.cfm?PRRFNBR=28682&S=22977,22978,27734,20070,22854,28682,12111,24608,24609,27091,24610,24604,16241,24603,12150 at Colorado Cyclist.
Still need to get the power kit separately from "Colorado Cyclist":http://www.coloradocyclist.com/common/products/productdisplay2_v2.cfm?PRRFNBR=27091&S=22977,22978,27734,20070,22854,28682,12111,24608,24609,27091,24610,24604,16241,24603,12150. The cadence thing is just $40 separately, but the power output kit is a cool $315 although this includes cadence and power output.
You can also get the whole thing direct from a big "Polar reseller":http://www.polar-usa.com/polar-packages.html for $690. This is a Polar S720i, a Power Output kit and a USB/IR connection. We don't really this last thing, although it is very convenient if you don't have a laptop.