It was common for retailers to request materials in kind; Jeannetty did not require that.
Morelot's ms. dated prior to 1798; Jeannetty's work was well-known by the early 1790s.
c.1797: 1 Troy Ounce platina (Estimate: 70% ore, retail) = Fr 12.20
c.1797: 1 Troy Oz. Pt (Ore at purity, retail) = Fr 17.43
c.1797: 1 Troy Oz. Platinum (Producer Price, Retail Mfg) = Fr 45.75 - 50.83
(~£ 2.13 - 2.37)
"We see snuff-boxes, spoons, spatulas in the hands of several individuals who leave the laboratory. The Once of Platinum costs Fr 45. - 50., not including the material that was provided to effect the reduction."
Citation: Cours élémentaire d'histoire naturelle pharmaceutique, ou description... Simon Morelot (1800)
In Paris you already manufactured from pure Platinum snuff boxes, watch chains, spoon, toothpick boxes and the like, worked at very cheap prices and very clean and tasteful. The price of commodities depends, as with gold and silver, according to the severity and the type of work he is slightly less than that of gold.