Which wide-angle zoom to buy?

I want to buy a wide-angle zoom lens for nikon d3200. Please suggest which one. My budget is not high. Suggest under 20k if possible. Or if something higher than this then i'll see to it as well.

Nikon

You have two choices of Nikkor lenses

* the 10-24 mm f/3.5~4 $900
* the 12-24 m f/4 $1, 225

Tokina makes a 12-24 mm f/4 which is an excellent alternative. It costs $400 and of all the third party lenses, Tokina produces the best ones

The Sigma 10-20mm is very good - if you can afford it, the Tokina 11-16mm f2.8 is even better.