A while ago I had two players in a group of 4 that would always be chattering about something, whether in game or out, and it started to get in the way of game time. I told them this, and the other two players agreed, but it was just their personalities that started to get rather talkitive, not just how they played.
I like to move the game along quickly so I asked everyone to pass notes instead of talking out loud to keep the flow going. It worked for about 3 sessions, then started to break down when they were confronted by a 'moral dilemma' (moral to them, I never thought they would have an issue to puzzle over).
Ever since then, if one of them would start to talk before descriptions of important details were done, I would let it go. They have left behind some valuable magic items and numerous other treasures simply because they would start doing things as soon as they could to get all the goods they could or move on. And I thought I liked to game fast, but it was just sorta ridiculous how little they cared about plot and character interaction - felt like I was DMing back in high school again, but we had all graduated from college.
All in all, I think it has to do with the player type and getting used to different settings. I like to challenge the players and have them talk about the events that took place and how they beat the BBEG, not how good their characters are. I stopped DMing that group and moved on since I felt like I didn't fit as a good DM; after all I wasn't having fun anymore.
But I never charged them anything for talking, and at most I think I would only take away XP, where it really hurts the character development. $ is $, and I work hard to earn every penny of it. No need to sap some away for petty reasons.