$10 per watt is the general rule of thumb plus the cost of a regulator and cable.
Looks to be a good price to me.
Should be pushing around 25 - 30amps per day back into the batteries. (thoretically speaking working on 70% efficiency and 8 hour avg. exposure)
Very good little setup! I must admit I am quit the fan of the fold away designs
I believe Derrick Bester of http://www.sidewinder.com.au
also sells a similar product - not sure on the $ though and I'm having a few internet issues this morning so I cant check