A kit that would include tools that would help you get along a little easier.
Included: Sunglasses (reduces or eliminates the effect of flash nades), Oil (use on a door to make it open soundlessly, for example the back door in cs_assault) and Soundless Hook (this one I'm not sure about, it might make the hook too unbalanced). Feel free to suggest some others additions, I'm outta ideas.
Cost: 5 credits
Benefits: Able to sneak easily, or defend an area without worrying about flashes.
Downsides: Oil takes place of knife, sunglasses darken your screen (so don't use it on dark maps! )