We have an awesome tech person at our school who has been searching for cheaper alternatives that work in just the same fashion. Last year, she showed us one that uses a stylis pen to operate the board rather than your finger, much like the Promethean Boards, which I also love. It was the perfect solution!
It is called a Mimio.
The longer piece is placed next to your working surface. Once hooked into your computer, it turns that surface into an interactive board!
I just had to be one of the first ones to use it in the classroom. I have had it in my room for a year now and love it! It barely takes up space and I can use the surface as a whiteboard when I am not working on the Mimio.
Here are a few of my students trying it out this week. We were doing a lesson on 3 digit place value.
They click on the dice to roll them.
They then write and state the number they created.
Simple but VERY effective.
In this particular lesson, there were a few other activites on 3 digit place value that the children had a chance to try as well. I love getting the kids on here!
I can't take credit for creating this though. There are a TON of great smartboard, powerpoint, and other creative lessons on a website called: Rockingham County Public School Resources
You can pretty much find any grade and subject on there. I found this one on the second grade math resources HERE.
This is a county in Virginia so concepts are categorized by SOLS(Standards Of Learning). However, I don't think you will have a problem finding what you need.
Hope you find some great ideas there!