The Eureka Gold was a native 20 kHz gold prospecting detector with a 60 kHz harmonic selectable frequency for tiny gold nugget targets in mild ground and a under harmonic of 6.4 kHz. It has lots of knobs and switches and has no display. I used one for a while and found the 20 kHz operation to be excellent. 60 kHz since it was not a “true” 60 kHz along with 6.4 kHz were fairly unstable where I used them so eventually moved on to something else mainly the Goldmonster 1000 which replaced the Eureka Gold. I did not find its tracking ground balance or its iron discrimination to be all that great but I hunt in some nasty ground. Unless you hip or chest mount the control box, you are swinging an 5.5 lbs detector. Like bigtim1973 said, the rechargeable battery packs are probably long dead. There were some that came with an AA battery tray.
At one time, I think it was around 2014???, Minelab was basically giving away a Eureka Gold with the full price purchase of their GPX 4800 pulse induction gold prospecting detector. That’s how I got mine. I kept the GPX 4800 for a couple of years but sold the Eureka Gold pretty quick since I liked my Garrett AT Gold and my 19kHz Tesoro Lobo Super Traq better for gold prospecting and then went with the Goldmonster 1000 when it came out.
I would not pay more than $200 either if it turns on. Way less if it doesn’t have a working battery pack.