On the forty-second page of “Gardening When It Counts: Growing Food in Hard Times” author Steve Solomon wrote (emphasis added):
only four tools are essential: an ordinary combination shovel, a common hoe, a bow rake, and a 10– to 12–inch-long (25– to 30–centimeter) metal file (with handle) to periodically sharpen the shovel and hoe. If you are not fit, then you'll probably want to get someone else to work the earth for you the first time it is dug (or have it rototilled). If you are physically unable to shovel or hoe, you'll probably have to consider the second-rate practice of mulch gardening. I do not recommend permanent mulching unless, because of infirmity, there is no choice.
Please do not buy cheap discount store tools. If you are what Australians call "skint," (broke), you will do better pawing through secondhand shops until you find good ones. Where can you find quality new tools? I suggest a visit to a commercial hardware store, landscaper's or nursery supply company, or contractor's supply store and inspect what they sell to tradespeople. People working with such tools all day long can't afford to be resharpening one every half hour, breaking one every other day, or wearing them out every few months. Quality tools aren't cheap, but they work out to be the least costly in the long run.
On the other hand, in some mail-order catalogs you'll find tools, supposedly of extraordinary quality, offered at extraordinary prices. These status symbols are usually no more effective or long-lasting than the ordinary tradespersons' gear.
There are different kinds of shovels and spades, each designed for a different task. Industrial hardware stores and landscapers' have makers' catalogs on hand showing each design, weight, and size. I suggest you ask to study the catalog—and take your time with this.
Some shovels are designed to move piles of loose material from one place to another—for example, to fill a wheelbarrow with sand or small gravel that is spooned up from a heap of loose material. Blades on these kinds of shovels are broad and deeply curved so as to hold a lot, like a soup spoon. This tool is designed to be thrust into a heap of soft material with the strength of the arm and upper body and then to life out a large measure, so the blade rarely has a rolled-over top (to cushion the foot pressing it into the earth). It is not easy to dig into the earth with one of these.