Since this is the Gold section, look for a used detector, such as Tesoro Lobo ST, Fisher Gold Bug 2, Fisher Gold Bug pro and/or Whites MXT, GMT, GM2 thru GM4 (as well as various Gold specific MineLabs). The Garrett AT Gold is too new to find many used ones out there, otherwise it would also be on the list. Avoid any detector not specifically optimized for finding Gold (there are few gold detectors that can be used for other THing, but most general purpose detectors won't find smaller Gold, ie, under a gram).
Look on Ebay, CraigsList and contact any Gold prospecting clubs in your area and see who has a used detector for sale. I found my GM2 and GM VSat on eBay (they are quite capable).
Then join a Gold club and learn how to use it (native Gold is a lot harder to find than Coins, so get all the help you can get).
If you want to hunt for more than Gold, you might end up with a different detector for that purpose (I have different detectors for different hunting goals).