I have what I would call a professional bias: when I read about prices from old times, I think about how much it would be today. You might not know it but for different reasons, prices are changing over time meaning that you can buy more or less goods for the same amount of money. This is what is called inflation.
This has been going on since the human kind invented money (don’t worry, I won’t bother you much longer with details) and it explains why the real value (real in economics) is different than the nominal one (again in economics).

When I read thanks to Twitter that the oldest reference to tea in Britain had been found in a document from 1644 I was really curious but when I read that there was a price for a cup of green tea from China, I was even more.
4 shillings for a cup… How much would this amount of money be worth now? And how would it compare to our standards?

As I explained earlier, to know that, you just need to find either a table with all the figures of the yearly inflation from 1644 to nowadays or one showing the real value of the money between those two time periods.
The problem being that statistical institutes weren’t around so early and the goods making the price basket weren’t the same now and them. Both things making it quite complex to make extrapolations.
Luckily, I found two papers dealing with this topic in Great Britain. The first is Seven Centuries of the Prices of Consumables, Compared with Builders’ Wage Rate by E.H. Phelps Brown and Sheila V. Hopkins in Economica, New Series, Vol. 23, No. 92 (Nov. 1956) and the second is Inflation: the value of the pound 1750-2011, Research paper 12/31 from the House of Commons Library (29 May 2012).
With these two papers combined, it should be possible to go as far as 1244 and back to 2011. I said “should” because the method used in both papers is not really the same and the second one uses also several methods to give the members of the House of Commons an approach and a range for the oldest inflation rates.

So by mere calculation (those that followed until now will tell me that there is a gap in my years but converting pounds from 2011 to 2017 is easily done thanks to some tools found on the Internet), the 4 shillings of 1644 become between 37.22 and 46.50 pounds of today or between 42.20 and 52.72 euros.

To give you (and me) an idea, I looked at prices for 100 grams of green tea of China and I found a price between 5 and 68 euros depending on different things, which for a cup of tea with let’s say 3 grams of tea in it would make a price between 0.15 and 2.04 euros.
Even if the price would probably be a little higher (people have to make a living out of it) and if there might be a few mistakes in the conversion to real value (something quite understandable due to lapse of time under consideration), the difference shows us that in 1644, tea was really a luxurious product and that drinking a cup of tea was the sign of belonging to the upper class.

I am glad I don’t live back in these times as I wouldn’t be able to indulge in tea drinking and that would be really sad.