Lots of good choices out there.
After a couple other holsters, I finally settled on a Milt Sparks Criterion IWB.
Here's what I recommend:
Get yourself a suitable gunbelt that will meet your dress needs. A holster without a decent belt is a bad match up that will leave you frustrated. You MUST have good support for the holster and the weight of a loaded pistol.
Visit some gun shops or gun shows and try out some holsters for fit and function. Of special note:
- The holster should retain the weapon, whether with a retention strap or without a retention strap, in whatever activity you expect to be performing.
- The holster should retain its form, especially without the weapon inserted, in order to facilitate re-holstering your weapon with ease. This is more important for IWB holsters, as they are worn between the body and the belt which will lead to compression of the holster by your belt.
- Your holster MUST adequately protect your weapon's trigger and prevent anything from reaching it with the weapon holstered. This is especially important with your Glock, as it lacks an actual safety to prevent pulling the trigger.
- Your holster, when worn, should retain its position without shifting. It should not shift its cant (the angle your weapon is presented), nor should it shift position around your waist.
Good holsters (and gunbelts) aren't cheap. If the price is throwing you, then think about it in terms of the money you spent on the gun and the ammunition you run through the pistol. A good holster will run you about $80 to $120 for starters, give or take. That's what...4 to 6 boxes of Winchester Whitebox 9mm?
It's also entirely possible you'll end up with 2 or 3 holsters over the years, as you try others. Nothing wrong with that, and nothing that many of us haven't done, either. But if you follow the general guidelines I posted, you'll be able to find a decent holster to start with.