I had damaged both my USB drives with a bad peripheral device and neither were working. When I tool my computer to the store, Apple gave me an estimate of $450 to replace the I/O board.
The repair went great. I was done in 10 minutes.
Be sure to order the proper tools with your parts. This made everything easy.
T5 Torx Screwdriver
P5 Pentalobe Screwdriver Retina MacBook Pro and Air
MacBook Air 13" (Mid 2011) I/O Board