NB Titler Pro 3 costs $99 when you upgrade to Sony Vegas 13. It's a completely independent install, though, and it asks which programs you'll be using it with. I think it polls your system and provides the necessary hooks to the NLEs you use (not sure about that, though). It then shows up in Edius and Vegas (and other video editing programs such as After Effects). There's no need to buy an NLE-specific version.
The Edius offer is for NB Video Essentials 3, a different plug-in. NB is offering it free to registered users of Edius Pro 7. I found out about it on the Grass Valley Forum. I don't know if it will work with Vegas or not. Video Essentials doesn't do titles. It does things like image mapping. For instance, you could map a video to the side of a building, to make it look like the video was playing there. I haven't experimented with it in 3D yet, but seems to me the worst case is that you'd have to do the mapping twice for split right/left files.