Hi Kev, welcome. The best advice would be, make contact with a prospecting club in your area.
These are not only great for advice but also hands on trialing of gear.
Our club has a few loan machines but the big plus is they actually show you how to setup and use.
You may find detecting is not for you. Best to find this out before you invest your hard earned money.
The other thing you can do if you do not want to purchase a new machine is keep an eye on the sales here or at the club.
Good luck
Cheers HH