From the article it says a wealthy laborers tunic is one shilling. Somewhere else it mentions max salary for a laborer of £2 (40 shillings). Both around the 1300s.

In the UK today a £40k salary is pretty good, above the median and AVG, so at most a decent tunic cost like £1000 in today's money (at most $1500), probably less. So it the right order of magnitude, but over-estimated.

Cloth was relatively expensive, but leather & fur was relatively cheap.