Ronald, number 3 and number 4 are top notch IWB's and moderately priced. snipercountry.com/sig-sauer-p320-holster/

Ron, in my opinion having purchased many holsters trying to find the right one I would go to your local gun shop and ask them if they will allow you to try different types of holsters on and that may help give you a better idea of the type of holster you would like. What I finally found that I like and would recommend looking into besides definitely trying different ones on is an IWB and OWB hybrid kydex and leather holster which provides you the option to carry your firearm both inside and outside the waist while giving you the comfort of the displaced weight especially with your P320 across your belt and leather against your skin while in the waist and the flexibility of wearing it outside the waist. Suggesting a certain brand I think would be like going with Ford or Chevy, you really just have to find what YOU like and what works for YOU but as far as functionality and options try a hybrid kydex and leather holster in my opinion.

Ron - I use the Alien Gear. Best choice I've ever made. AlienGear.com

Ron - I have no direct experience with the P320, but I have been using Blade Tech Nano holsters for several years, and really like them. Comfortable, durable, and they just feel right to me. Second recommendation would be Alien Gear. So many to choose from, and so little time! LOL Good luck!