After trying several brands of OWB holsters for Sigs, I have settled on two that I favor. The first is the belt scabbard holster in horsehide from Kramer, which holds the gun firmly without movement, but allows an easy draw. These cost over $100 directly from the company, but can often be found on Ebay for half that amount, if you are patient. I use this for my Sig P229, as shown:
More in the price range you mentioned is the DeSantis speed scabbard holster in leather, which is available from many vendors in the $45 range. This holster works very well and offers good retention at a reasonable price. Do a Google search to find vendors. Here is my Sig P239 in this holster:
http://i116.photobucket.com/albums/o...9holster04.jpg
http://i116.photobucket.com/albums/o...9Holster20.jpg