Some Thoughts on the Waite-Smith Deck
There are hundreds, maybe thousands, of commercially-available Tarot decks. There are many more made by individual artists for their own use. Beyond that, there are hundreds of Oracle decks out there, made for the same sort of divination as Tarot cards but with unique designs and their own particular systems of symbols & correspondences. Many readers pride themselves on amassing an enormous collection of these.
Because of that, some people are surprised that I own and use a single deck. Technically, I own a few, but they're various printings of the same design: the Waite-Smith deck, sometimes called the Rider-Waite deck, designed by Arthur Edward Waite and Pamela Coleman Smith in the early 20th century. This is almost certainly the Tarot deck you think of when someone says the name of a card. It's in the public domain, and it's the deck I use everywhere on this site.
The Waite-Smith deck is not the original Tarot deck — it's several centuries late for that — but it had such a massive influence on our popular understanding of Tarot that almost every other deck you use is based on Waite & Smith's work, whether consciously or not. If the deck you use has cards called "The High Priestess" and "The Hierophant" but not "The Papess" and "The Pope," then your deck inherited some of the changes Waite and Smith made.
That said, I think some people worry that they need to buy the "correct" deck to start reading cards, or that people who buy anything but the Waite-Smith deck are somehow taking things less seriously. This is wrong. There is nothing special about the Waite-Smith deck, or about Tarot cards in general. An oracle deck or a deck of playing cards works just as well. I once met someone in a Discord server who practiced divination using a five-color Magic the Gathering deck. In Postmodern Magic, Patrick Dunn suggests making your own deck for divination, starting by using a deck of playing cards with random words written across them and slowly improving it until you have a deck of custom art.
If there's one advantage to using the "classic" deck, it's that virtually every resource on Tarot references it. That makes it a lot easier to learn what everyting means. I believe, somewhat controversially, that cards mean different things in different decks. You can't change the art without changing the meaning, and that does mean that choosing an obscure deck mgiht require you to feel out the intricacies of each card on your own. That's an easier task than you might think, and you could certainly do it even as a beginner. In the end, you'll be a better reader for it.
The most important thing about the deck you use is — and this too is stolen from Postmodern Magic — you need to believe it will work. Choose a deck that helps you feel confident in using it, whatever that may be for you. For me, it's always been the Waite-Smith deck.