You can simply set up find my iPhone and then track it... I don't see why many people still don't know that.
If you lost your iphone, wallet, and car keys....which one would you be bummed over losing the most?
take into consideration:
1)you have insurance on your phone which can be replaced.
2) Couple of pictures in the wallet that are irreplaceable
3) car keys have chips that cost bling bling
?