Hot summer blowout secret gift

Today , i finished the 3rd week's money for summer blowout and i've unlocked this :
I think it's a key.
But it's strange...800 stardollars for 20 things [some clothes , ugly] and they give to you just a simple KEY ?? No..i don't think so...i think it's a hey who unlock a thing..but wich thing ??
Or a key who give to us money ..or a magic key =]]
I don't know.
What do you think about this ? What do you think...for what is the key ??