What do the "c," "R," and UR" really mean?

[StormcloudCreations]

For the most part, a C means that it is common on most, if not all, the planets. Occasionally, an item may be slightly rarer on some planets than others, but for the most part, the Ratings apply to the item itself and its overall rarity in the galaxy.

The rarities can change, and do change, very frequently during the game. So now you can add the strategy of storing up a few items and wait for them to get more rare and then sell them later.