I did read a few chapters of
Tribute of Death last night and the writing style, story, and level of background info seem pretty similar to the first two Simon & Schuster published ones that I have in DTB. I'm enjoying the book so far.
The production was a little sloppy though. There are enough typos that I've noticed them, but not enough to ruin the story for me, although, of course, YMMV depending on how sensitive you are to this sort of thing. The typos actually looked more like errors from converting to e-book format (words run together, part of a line missing, etc.) than real typos, and I think the book doesn't need an editor as much as just a good proof-reader. And, of course, I've also seen worse from some of the "established" publishers
I did take a look at the author's website and blog, and apparently he has not been able to find a publisher for this fourth one, or a possible fifth one, so that's why he's trying the self-pub route. He mentions this one on sale at Amazon for $0.99, so that's apparently not a pricing error, and Koland is probably right that the $9.99 at B&N is the error.
Anyway, if you like this sort of thing (non-cozy historical mysteries with a fair amount of background) you will probably like this series, and if you don't you won't. And you can try one out, even if it's not the first one, for a cheap price.