Good day my name is ***** ***** is a pleasure to help you.
The Works of the Rev. John Newton, Late Rector of the United Parishes of St. Mary Woolnoth and St. Mary Woolchurch
A first edition of the set has a retail value range of $22.00 to $40.00 per volume or $120.00 to $240.00 for a 6 vol. set.
As you may have discovered no complete set is currently on the market, so you can set your price.