You can always go with the 3rd party Wide angle zoom Lens if cost is your concern. They have been making very good quality Lenses so far. Especially for the Wide Angle Zoom lens, I rarely seen any complaint from users who have bought it, whatever the brand is (Sigma, Tokina, Tamron, Nikon or Canon).
But, if you only want Nikon in your lens arsenal then the Nikkor 12-24 f/4 DX is a good buy. You'll love this lens like I do.