The 15th December is the 8th birthday of The Sims Freeplay! You may have already found the gift at the front of one of your sims houses, if not remember to open the gift to get a free fortune box to celebrate before the end of this update:
Happy Birthday to The Sims Freeplay!
The Girl Who Games 
I can’t find my box!
Try a different house, it will be at one of them.
I got my gift, and I see the furniture and stuff in my inventory, but I don’t see the clothes (from the gift) in the wardrobe. Do I have to have a certain store that it is purchased at, and it would just be free then, unlocked/available then?
Have you unlocked all the life stages yet? It might be the clothes are available for a life stage you haven’t unlocked yet so you can’t see the clothes until you unlock them.