I have to suggest the Old Faithful IWB quick assembly kit. $50 delivered and all you have to do is screw it together. Great retention, great quality components American made, and 50 year warranty. They make one for about every pistol and if you want to live on the edge they will send you an unformed kydex that you can do on your own, not that I would suggest it.
Check them out, if they make one for your pistol you'll be glad you did. I have been using one for my Nano and its really comfortable.
SIG 1911 .45 ACP
SIG P229R 9mm
Beretta BU9 Nano 9mm
Beretta 84FS .380 ACP
Ruger MKIII 22/45 Target .22LR
PWS (Primary Weapons Systems) MK114 5.56