Guides
The parts a calculator cannot tell you
Three short pieces, written for somebody about to sell something and unsure whether they are about to be taken advantage of.
The most expensive misunderstanding in the trade, and the one every calculator on the internet quietly encourages.
5 min read
The chain from your kitchen drawer to the refinery, who takes what along the way, and why the same chain gets four different prices.
6 min read
What a stamp does and does not prove, and the checks you can do at home without damaging anything.
5 min read