The Sum Of Saving Knowledge: Or A Brief Sum Of Christian Doctrine, Contained in the Holy Scriptures and Holden Forth in the Westminster Confession of Faith and Catechisms; Together with The Practical Use Thereof by David Dickson and James Durham.
This used to be included in Scottish editions of the Westminster Confession of Faith and Larger and Shorter Catechisms. Here's some history of it.
It can be found online here.
This would be just a short pamphlet, about 30-35 pages total, so I'd recommend a price range of $1-$5, and hope it goes for $1.
