Every time you prestige, you will receive a prestige token that can be spent on rewards in the prestige shop; meaning you are in control of what you get.
Also see our page: Prestige Symbols MW2, Black Ops, MW3
The last known reward is unlocking a single item from a custom class that you can carry throughout the rest of the prestige level. This would mostly likely mean you can pick your favorite weapon, perk, equipment or whatever you like and use it throughout the entire next rank instead of waiting to unlock it once again. Finally, if you are one of those people who enjoy prestige mode, you now have the option to reset all stats after prestiging.
You will be rewarded with prestige tokens in Modern Warfare 3 every time you prestige, However, if you have prestiged in any of the previous Call of Duty games, you will also be rewarded with a prestige token at the start of Modern Warfare 3. It is uncertain if you receive a prestige token for every level of prestige in previous games or just one token for any amount greater than one. There are some players who could have multiple tokens at the start of Modern Warfare 3!
In the shop, you can spend your tokens on the following rewards:
- Extra Custom Class
- Double XP (two hours in-game time)
- Double Weapon XP
- Regular Package (Callsign Title and Emblem)
- Unlock Gear (Choose one item that’s unlocked permanently)
- Hardened Package
- Veteran Package
- Reset All Stats (resets everything, including your Prestige Level)
Here is a video of Robert Bowling talking about the prestige shop.