I bet you get some "varied" opinions on this question.
Some will make some people happy and some will make some people angry.
A "fair price",
I think a fair price would be around $200,
A good deal would be less than $200..
There are lots of deals out there from time to time.
I started late collecting Jenkin's Battle of Monongahela and have done pretty well.
I'm still missing a few sets, but I will learn to live without them.
The Collector's Page on Treefrog has someone unloading all his Jenkins right now and BM06 is included in it.
You will probably pay more on Ebay, as they draw a bigger audience than just Treefrog members.
Personally, I love Ebay shopping, I just bought a Britain's Civil War Wagon yesterday and I think I got a good deal..
Considering how rarely they (BM06's) appear for sale, I think $200 would be a "fair price".