In order to get all weapons and full armor for free you MUST do the following steps:
1- Start a new game.
2- After the game starts, hit the (~) key, its the one located before (1) and above (Tab), a console window should appear from the top of the screen.
3- Now type (sv_cheats 1)
4- Hit (Enter) then type (restart) and hit (Enter).
5- Your game will restart now.
6- After it has restarted, you MUST type in the console window (bind v "impulse 101"), then hit (Enter).
Now whenever you press the letter (V), you will automatically have new weapons and armor in your inventory... Keep pressing untill they're full.
P.S: During a certain fight pressing (V) is a great way to gain lost armor, thus living longer.