I agree in the main with pathers post that you start cheaply. This hobby is not for everyone, as most of us longtimers know, and the chance exists you wont stick with it. Thems just the facts.
But I differ on one point. DO NOT buy a "cheap" garden trowel. Get a purpose built tool for digging in the earth. Imagine you had to dig a large hole and were handed a flimsy, poorly tempered shovel. First time you bore down on that blade in the hard earth and it gave way, what would you think?
For $8-15 you can get a Wilcox 102 or their longer version of the same, which I suggest you get. These are forgotten nowadays in the rush to by Lesche's, Predators and all the other newfangled, much hyped and expensive tools. The Wilcox 102 is the original detecting trowel and I have never seen or even heard of anyone breaking one. No less and expert than Ed Fedory once named it as the ONE tool he wouldnt be without.
You dont always need the best, but shoddy will always let you down.