I remember the stuff was stupid cheap when it came out, $10.99 / 50 IIRC. I see it now for $13.99 / 50 while you can get the American Eagle brass reloadable for about the same price. I read a review on the Kel-Tec sub2k and they were showing how unstable these cases were with that firearm.
Maybe vendors are just keep it a dollar cheaper than AE knowing that people will buy up everything they sell. That's what I'd do, better margins that way. Your average shooter could care less if it's brass or aluminum. You need a keyboard, internet connection, and terrible grammar to really understand firearms.