Although the traditional Soroban has 13 rods, it is generally recommended that you use a basic version of the Soroban for young children. The Pacchi which only has 3 rods with different colours is the representation that is used in Heguru classes. Tomoe Soroban is also the cheapest place I know where to find this.
You can learn how to count using the Soroban from the following videos. Counting from 1 to 10:
11 to 20:
21 to 30:
You can get also get slide presentations and PDF files for 1 to 100 from the BrillKids’ Free Downloads area.
For more information on teaching Soroban, here are a couple of sites on this:
You can view the success with Math Secret in the video below: