There are a FEW Recipes out there, but the one I tried IMO was AWFUL. DH said he liked it, but I couldn't even stomach it. Plus, the ingredients could possibly cost more and be more difficult to get than for regular bread.
There's one I have yet to try, and that's Diedre's "For Real" Low Carb Bread on the Y-Tube. You might take a look at that and the ingredients before investing in a machine. You could even try it the old fashioned way first.
As far as machines go, you don't have to spend $300 on a machine. I got mine for about $170 and it makes perfectly nice bread. Even with an expensive Z machine, you have to babysit it a bit in the beginning to make sure you don't need to add a little water or flour since the humidity or dryness of the air can affect how much you need for a good dough ball.
I don't bake my bread in my machine. I like a standard shaped loaf and even the ones with a rectangular pan don't make it a standard size. The first time I did that I just dumped the dough out and put it in a loaf pan without kneading or properly shaping it and it came out just fine.
Oh, and no preservatives means it'll go bad quickly, but you can always slice and freeze the slices. That's what I have to do when I make bread.