Hm, I was trying to dig up some facts on it, and figuring out where numbers might come from...
In 1816 the UK reformed its currency. The gold sovereign, worth 1 GBP was introduced. It contained 7.322 grams of gold. The Feb 2020 price of 1 gram gold is $50.44 USD, so $369.32. There were 20 shillings in the pre-decimal pound sterling. So 1 shilling is $18.47.
So 15 shillings would have equalled around $277 for the week. If you want to go by that basis...