Ahh, a topic after my own heart. As FtWildernessGuy mentioned, there are two arcades at the Fort. The one by Crockett's tavern is back in the corner, and is rather small, with maybe 10-15 games total. There is a second level with a few arcade games, but most are on the bottom level. It is not much larger than a very large walk in closet...lol.
The arcade by the Meadows trading post is located in the pool area, it is larger and has a wider selection.
Most games haven't been a quarter at Disney for a while now. And that's not just Disney, that's arcades in general. Most of the games will run 50 cents to a dollar, although the "cheaper" arcade will be the one by Crockett's Tavern. It actually still has a couple quarter games (Ms Pacman and a rather fun old style baseball game).
I remember when I was a kid we used to save up all our money to visit the arcades while we were at Disney. The Contemporary arcade was our favorite, it is the largest one in Disney. Well, that is, it was, but now they are moving it to the 4th floor and removing a large part of my early Disney history, which I'm not happy about
We used to be able to take our 20 bucks and make it last for hours while our parents enjoyed the Top of the World at the Contemporary. Now, 20 bucks MIGHT last you an hour :/ Of course, depending on what games they want to play. If they want to play the newest games, it's going to cost more, and the money is going to go faster, since the gameplay time is about the same as if they spent a quarter on one of the older games.