How to fix my iphone4s speaker?

Okay here's my problem, my iphone's speaker is not working when I call or receive them okay, but when i play videos in iphone i can listen to the audio but when i call it doesn't. What shall I do?

Take it to apple, if you are still under warranty they'll just replace the phone for free. If not they'll charge you to fix the speaker. But i'm sure they are pricey… There are people who fix it much cheaper. I went on craigslist and found someone in my city who fixed my iphone speaker and replaced my cracked back screen for very cheap. 1/2 of what i wouldve paid through apple