It's not often I am planning for the season ahead but I found myself with the opportunity to buy a S&W (tm) model 640. It was an original series pre-lock original J-Frame 38SPL only. 
They are not the rage any more so I got it a fair price at my local LGS. 

I am also a fan of Kydex holsters. They are lightweight and thin. I was surprised to find that not a lot was available for an original J-Frame. My old favorite IWB CompTac (I think it was called a ShirtTucker) is no longer made and my favorite ankle holster company Renegade had gone out of business. But, I am pleased to see that Wilderness has picked up the line. 

So, for IWB it seems that there are very little variances in the available holster designs. The first one that I tried was a Concealment Express that I found on Amazon for $40 shipped. (http://www.amazon.com/Concealment-Express-IWB-KYDEX-Holster/dp/B00UFEIHAQ/ref=sr_1_1?ie=UTF8&qid=1460577320&sr=8-1&keywords=concealment+express+642). How could I go wrong? It was a basic holster design with a large clip attachment in the center. Very common, very simple.

Their ad says that it fits a 442/642 - basically Airweight versions of my (older) 640. I emailed them to see if their holster would fit my 640. They replied that it was for a J-Frame. hmm. I clarified and they responded that they had not tried one specifically. Response was very quick. I decided to try one. It fit perfectly.

Well, to be honest I didn't like it. The clip was huge! My belts were simply dwarfed by it. I have an 1.5"-width super-thick Galco leather belt that is too thick for the majority of holsters - especially those with Kydex or synthetic clips. However, on this holster my belt was tiny. Wearing the holster it slid around in between the loops and my revolver's butt pivoted forward and back. I am also not a fan of putting the clip at the thickest part of the holster body and firearm.

The quality of the holster was good. The clip looked like it was one-size fits all holsters. Perhaps that is how they get the price so low. I emailed them about the clip and they never responded.

I think it would be fine for someone looking for an inexpensive holster that they would not be wearing for a long period of time or frequently. For me, I would rather pay additionally to get something that I could wear all-day, all the time. I sent it back. No use in having it sit in a drawer. 

So, that was my first try. lol

 Here is a pic of the holster's clip: