One of the metal detectors that MDE Gary Drayton uses is the Minelab CTX 3030, which sells for $2900 on Amazon with a 17" Smart Coil.

The metal detector I use on TV treasure hunting shows

What Metal Detectors Do They Use on The Curse of Oak Island?

Gary literally wrote the book on using the CTX 3030: Gary Drayton The CTX 3030 Beach and Water Hunter's Guide - Paperback

He also uses the Minelab GPX 5000 ($3999 on Amazon) and the Minelab EQUINOX 800 ($949 on Amazon) according to his Meet The Detexperts bio on the Minelab website.

One would need to find some decent Bobby Dazzlers to afford buying all these metal detectors.