Prestige is a reset-based system that allows you to gain major boosts albeit requiring a complete restart (with the exception of certain premium bonuses).
Soul EggsYou gain Soul Eggs by prestiging or completing certain missions. Each Soul Egg gives a permanent 10% boost to your income. It is recommended to prestige when you have over fifty Soul Eggs for your first prestige, giving a 500% (×5.1) boost. After that, it is recommended to prestige to double your soul eggs, or in other words prestige when the number of soul eggs you will get is equal to your current number of soul eggs. You will then restart to the Edible Egg farm, keeping only your Pro Permit, Epic Upgrades, mission history, Piggy Bank, and Soul Eggs.
When you prestige, you gain (prestige bonus)*(cash/1000000)^0.15 soul eggs.
Soul Food, an Epic Upgrade, strengthens the ability of Soul Eggs. Each level adds a 1% boost to all Soul Eggs (i.e. a level 4 would have a 14% boost). Soul Food has 140 levels, with a maximum of 150% bonus to egg value.
Prestige Bonus, an Epic Upgrade, makes prestiging give more Soul Eggs. Each level adds 10% more Soul Eggs at restart (i.e. a level 5 would have 50% more Soul Eggs than normal (i.e. 15,000 rather than 10,000)). Prestige Bonus has twenty levels, with a maximum of 200% bonus soul eggs when prestiging.