I dunno... spending a buncha money (in the right ways) will enable you to have good soil *faster*, but you can get there perfectly fine the slow and cheap-or-free way, too. At least anywhere I've lived.
I sure haven't spent any money on soil improvement here, despite just a few inches of clayey loam over top of clay subsoil you could make bricks outta. But I have put lots and lots of free amendments in -- moldy hay, leaves, chicken poo, composted down horse poo, not-yet-seeding weeds, the product of the official compost piles, etc etc.
For those who are trying to garden on something that is not really soil at all, like the bare subsoil of some modern subdivisions, it may be necessary to buy *something*, but it needn't be a large amount just to get started. Many materials can be scrounged.
I believe the only garden tools I've ever bought were a wheelbarrow ($60 new, big splurge, but it gets used in the barn etc much more than in the garden), a used shovel and rake and hoe for $2 at an auction, a used spade and two spading forks for $4 at another auction, a couple trowels for something like $5 at a garage sale, and my trusty bread knife which I use for a bazillion purposes in the garden, about $10 (new) every couple years when it gets replaced. Oh, and mom gave me a trio of Wall O' Waters several years ago, and another three last week. That adds up to less than a hundred dollars, and would be less if I'd gotten the wheelbarrow used.
(oh, almost forgot, I buy a new pair of gloves most years, so that's another five bucks)
It really needn't be expensive at all, particularly if a person is starting on a small scale (which is smart, and if you choose the right things to grow can still produce a pretty impressive amount of food)
JMHO,
Pat