May I ask you a question? I have a Garret ACE 400 that is great for finding things in parks and fields - I'm not confident it can find gold nuggets. But for nugget hunting, must I spend thousands of dollars, say on a minilab GPX 6000? Do you have any idea if the ACE 400 can do the job? Can you recommend something lower end that will get the job done in a capable way but wont slaughter my bank account? There are a lot of choices out there and it's all rather daunting.
Absolutely not. You can find nuggets with a variety of older machines as well as newer ones that sell for under a thousand dollars or right close to it.
I have found lots of nuggets with the Gold Bug Pro, and they're affordable. The Minelab Goldmonster is a proven machine, Nokta/Makro make good little machines (VLF's) as well that find the gold. As for PI's, you'd have to buy an older used Minelab SD, but they treated me to a lot of nuggets in the past and they deal with bad ground very well. My philosophy has kind of been to buy the detector I could afford (when I started out), then find enough gold to pay for it, then upgrade from there. It's gone well so far. What worries me is people with no experience (no previous nugget hunting/nugget shooting under their belt, no research background, no established contacts in placer operations, no real idea of where to go or who to contact to help them get started) that jump right into the game with a high-dollar machine only to find nothing but trash the first few times out, and then quickly give up.
You've got some good tips in responses above that direct you to some solid (YouTube) information providers, and there are other good sources on the Internet/on YouTube as well.
So, no, you don't need to spend thousands of dollars to get started, but you'll need to do some honest research/generate some good contacts/join some reputable clubs so you can hang out with like-minded people that will show you the ropes. Then, after lots of perseverance by getting lots of hours on your machine, and after lots of hours of digging trash, eventually with more perseverance, you'll get your coil over a nugget.
Good luck, and all the best,
Lanny