The Garrett AT gold pro is a very good all around metal detector that you can also use for hunting very small gold pickers and nuggets . Kellyco.com usually has very good prices on metal detectors.

I've been happy with my Nokta Legend pro pack... little more than you budgeted for the pro pack but it gives you an extra coil and
some other goodies that let you use it for quite a few different things. I haven't gotten it out to the gold fields yet, but it does well for
me on the beach, in the park, and in the water....