One of the biggest challenges my students face in Algebra class is retention of new material. They often demonstrate understanding in class, only to forget when they get home. While their class notes can help them, they often need a full demonstration to get them going again. Enter Sketchcast.
Sketchcast is a simple drawing program that can be directly applied to math class. Do your math lesson on sketchcast, post it to your blog (see below), and students can easily view it from home. This is a bit slow with just a mouse, but you can get a basic sketchpad for less than $100. You can get a wireless one for a bit more.