Which Micro Wind Turbine for 200-250 pounds (400-500 dollars)

 

I am looking to buy a Micro Wind Turbine for my RV .

I am looking at this model here which is in my price range of max 250
GBP (500 USD)

What do you think ?

http://www.envirotekpower.co.uk/page5.html

 

The output figures they are quoting are fantasy compared to other brands.
The other issue is tail-less down wind generators that size have not proven
to be a roaring success.

Would want to see some independent testing to substantiate their claims.