This may seem like a dumb question but...

[JS101]

Is there a way in Portal 2 to get all cosmetics for free? 

[bruno]

From what I know, you can use all of the taunts from the store using console commands, but I don't remember the commands themselves and if sv_cheats needs to be set to 1.
Also, please don't those awful fonts in your posts just for the sake of using them, since that's not only annoying, but also a very direct and free way to get banned.

[JS101]

its mp_earn_taunt <Put Gesture Name Here> to make both players
but taunt <Put Gesture Name Here> to only make you do the font