Dunno what it's worth, but I used to go detecting with a rubbish $50 detector from DSE many moons ago. Used to find money down the beach in the sand after a busy weekend by bathers. Even found a Victorian penny at one beach, along with a gold watch.
Well I went out that day, got the last one and it reduced to $50, plus I've foung $4.60 on the kerbside outside our house so it's 10% paid for itself already.