My sister created this site and she's put links to all kinds of pages with free and low-cost ideas to do with preschoolers. There are coloring pages, flannel board stories, learning pages, etc. Here's a quote from her blog:
"Ideasforpreschoolers.com is not necessarily about my ideas (although I have added a few) but about bringing all of the ideas from all of the great preschool sites out there together in an organized manner. This site is for children from 18 months to 5 years old.This is a great site! Check it out!
In the top left column there is a link called "Learning Activities". If you click this you will see all of the things your child should know before going to kindergarten (as stated in the World Book Encyclopedia and Learning Resources). I then went through this curriculum and created a page for each and ideas on how to teach that particular subject.
I also have pages on specific "Game Types". So if you are looking for a file folder game, felt board story, coloring pages, dot to dot pages or paper doll templates, this would be the place to go.
On this site you will also find several links to websites that have craft ideas for preschooler, nursery rhymes and other preschool songs, audio stories, and more."