Credits
For extra credits you can subscribe to Gamefly, Disney Movie Club and Netflix.
Disney Movie Club gives 306 Free Credits.
Gamefly gives 306 Free Credits.
Netflix gives 255 Free Credits.
Easy throwing knives, reactix without paying credits
Gain listed resources by buying the tactical knife in melee weapons, find a bomber or defuser mission and run through over and over until you gain desired amount of resources forfeiting and rebuking the tactical knife when it breaks and before finishing the mission. There is no real reason for bomb missions or forfeiting it is just easier for me to get knife kill streaks on these maps under any difficulty.