I brought my son's iPhone 4s here because it was turning off after he had dropped it. The back of the phone was also loose. They recommended a new battery and said the back needed to be replaced. Total would be $65 and done in 45 minutes.
I came back in an hour, and the tech said the phone wasn't fixable. Despite working with my phone for close to an hour, I wasn't charged.
I went home and found my old iPhone 4s (that I only replace with a new phone because the battery was bad) and brought it to The Apple Exchange. They replaced the battery in five minutes for $30. Bonus - I found the store on Yelp, and they had a buy $20 of service for $10 offer. So, I purchased it and actually only paid $20 for the battery and service.