Quoting ☠Rawr☠:" Does anyone have an idea about how much pre-k is on base for an E4? I know that it's different everywhere, ... [snip!] ... to wait for my daughter's new social security card to come in before they will even talk to me about enrolling her. Thanks!"
It is called Sure Start and is free with a waiting list.
The child has to be 3 and you sign up. I haven't gotten to use it though
A friend of mine got here as an E-3 with 3 kids and they all qualified immediately. He had another and she is 2 now. He said she'd already been enrolled. If you are on the program it is easier for siblings.