Mick Foley is just as well known for his style of dress as he is for his hardcore wrestling style. If you're looking to dress like Mick, you won't win any best-dressed contests. But you'll definitely turn people's heads and make them look at you for one reason or another.
Start with a basic black T-shirt, preferably oversized. For added effect, you could put one of those yellow smiley faces on the front or a "Wanted" poster with your picture on it.
Take an old flannel shirt with red and black checks on it. Tear off both sleeves and make sure the sleeve holes are really worn and frayed. Put the shirt on over the black T-shirt.
Add a pair of black pants. Black jeans work best for this ensemble. Any type of sneakers or other shoes can be added to complete the main costume.
Create your own "Mr. Socko" by taking a plain white sock and drawing a face on the toe end in black marker. This will go on your hand.
Complete the look by growing your hair as long as you can--definitely over your ears and down to the shoulders. Grow a full mustache and goatee and let the rest of your face go relatively unshaven as well.
Of course, you can always dress like Foley's alter ego, Mankind. For this, wear a white, long-sleeved dress shirt over the T-shirt, backwards and unbuttoned. Find a Hannibal Lecter style leather mask that covers your forehead and nose. To dress like Foley's other personality, Dude Love, this mainly involves a tie-dyed T-shirt and a pair of John Lennon style sunglasses.