I would recommend starting with the introduction section of one of the rulebooks. The big ass rulebooks lay it all out for beginners, from the history of the imperium to an overview of the various alien factions. From there you can dive into novels and stuff.
The 3rd and 4th edition rulebooks are my personal favorites, although those are pretty dated if you’re looking for modern lore on Primaris marines, Votann, new Eldar factions, or the return of the Emperor’s holy sons [REDACTED] and [REDACTED].
If you’re interested in a specific faction, that faction’s codex will have reams of lore.
Immune to market fluctuations. Based on years working and salary so if you worked a long time then retired and lived for a long time you may get more money than if you had a bag of cash in the market. It lasts until you die and your spouse can inherit it so it provides stability for you and your partner for the rest of your lives instead of having to guess how many more years you’re going to live and dividing your savings by number of years left. Removes that stress of outliving your guess and running out of cash.