UPDATE:
I've been pretty busy with a number of other projects since I first posted this, but I'm finally getting ready for some serious looking and doing. Toward that end, I've sent some inquiries to Solidworks (which apparently has a CAM add-on) and taken a second look at several options for Alibre add-ons.
The first was sprutCAM (mentioned in my original posting. I went to their website again, and tried to ask about pricing on two different message pages. Both of them returned errors. And the only phone number anywhere on the website appears to be one in Russia. They do list a US office in Wisconsin, but no phone # ... Something smells mighty fishy here!
My second effort was look at MecSoft. I'd originlly mentioned that their software is $600 and up. But now they're mentioning a free (though limited) version called "Freemill" for Alibre Design. I've sent an inquiry to find out if it also works with Atom.
Thirdly, I've taken Boswell's suggestion and made contct with BobCAD/CAM, just to see if I can get some kind of discount.
I'll post additional information as I receive it. Thanks again to all who responded to my original question.