You see, Traveller has this great economics simulation system, so you can trade goods across the planets, adjusting costs for local conditions and some random factors. Prices fluxuate. This is realistic and can be fun, but tedious. Why am I mentioning this, because I hate price lists that are exactly the same across the world. Characters tend to do a lot of travelling, so the prices should shift. Making a chart for each region is tedious. So I created the following chart
5 Book Cost plus a coin
6-8 Book Cost
9 Book Cost minus a coin
You need to create modifiers, on the fly, for scarcity and bumper crops, season, and so on.