The last time I looked it was $460 +/- and ounce.
Now gold is not really that price except for flour gold. If you find a nugget with quartz in it, jewlery grade nuggets and other speciments you might get twice that.
What you really do is save all the black sands that you find. Seperate out the magnetic materials and collect it. You don't pan out the materials from your sluice box until you get home. Eventually there are places (I haven't done it yet) that will process the material. You may end up with some silver, platninum, galena and other minerals besides gold trapped in the other materials.