Cheat to disable police wanted levels

There doesn't appear to be any cheat codes for the game that I can find. However, if you defeat Nemesis on Hard Mode he will drop something that gives you benefit.

• First Kill - Eagle Parts A
• Second Kill - Eagle Parts B
• Third Kill - First Aid Spray Box
• Forth Kill - M37 Parts A
• Fifth Kill - M37 Parts B
• Sixth Kill - First Aid Spray Box
• Seventh Kill - Infinite Ammo for One Weapon

It appears as though you must beat the game several times, and on different difficulties, to unlock everything.

Source

In reference to the link that you have added: What you are seeing on that website would be Hex Editing saved game files to give you items or change things around. It is much easier to hex edit saved game files with the PC version of the game than the PS version. The two versions share the same gamesave file format, but it would require much more effort to move a game save between your Playstation and a PC.

If you are playing on a PC here is a link that you might find helpful: RE3 Hex Editing - GameFaqs Guide

If you are playing on a PSX, PS2, or PS3 then this will quickly become a how to guide that you can probably find elsewhere.

No, there aren't any cheat codes in the Xbox 360 version of Mass Effect 3.

If you're having trouble with money or combat, you've got several options. At any point you can turn the difficulty down in the options menu if you think the combat is a bit too challenging. Further, the more you explore the galaxy, probe planets and scan systems, the more credits and other items you'll acquire.

If you do this early on in the campaign, you should have plenty of resources and find yourself having an easy time as you continue.

Further, if you download and install the free Kingdoms of Amalur demo, you can unlock a couple of bonuses in Mass Effect 3 - one is the Chakram Launcher, which is kind of a super-powered charge attack assault rifle, and the other is a unique armor set you get from the beginning of the game. Both of these could be considered somewhat of a cheat. :)