What you actually need to start playing
You have chosen a game, or you are nearly there. And then the next doubt arrives: do I need a mountain of gear before I can play? Miniatures, mats, screens, piles of dice, expensive shelves full of accessories? The answer is reassuringly short. For almost any roleplaying game, you need surprisingly little.
Here is what truly matters, what is nice but optional, and what you can safely skip until you know you enjoy the hobby.
What truly matters
Three things, and that is nearly all.
The first is the game itself. A rulebook or a starter box tells you how everything works and usually gives you enough to play those first adventures. A starter box often includes a ready-made adventure, and sometimes even dice and cards, so you literally need nothing else.
The second is the way the game handles chance, and that differs from game to game. Most games use dice. Sometimes those are ordinary six-sided dice you probably already own; others ask for a set of many-sided dice, with the famous twenty-sider as its best-known member. A single set is enough to start; there is no need to buy a drawer full. But not every game runs on dice. Some use playing cards, and the occasional game something else entirely: Dread, for instance, has you pull blocks from a wobbling tower, the tension rising until it topples. So check what your game asks for before you buy anything; it is always stated at the front of the book or on the box.
The third is you and the people you play with. For most games that means a group plus someone to run the game. For solo games, you are the only one needed. How to find players when you do not yet have a group is a story of its own, and we are saving it for a later piece.
Add paper and a pen to track your character and a few notes, and you are ready to play. That is all.
Nice, but not required
Once you find you enjoy it, a few things make playing more pleasant without being necessary.
A set of dice that is truly your own feels, to many players, like a small ritual. A game master screen helps the person running the game keep notes and tables close at hand. Loose character sheets, printed or from a booklet, keep your details tidy. And a quiet spot with enough table space does more for the mood than any accessory.
These are things you pick up along the way, not in advance. Let your first session tell you what you are missing.
What you can safely skip
There is a whole world of miniatures, terrain, battle mats, and deluxe screens. They are lovely, and for some players a hobby in themselves, but for your first steps they are pure excess. Many games play perfectly well in your head, with a single sketch on paper when needed.
Do not buy anything just because it seems to belong. Most expensive accessories solve a problem you do not yet have as a beginner.
And then?
In short: the game, a set of dice that fits it, something to write on, and people to play with. Everything above that is taste, and it comes on its own later.
If you have not settled on a game yet, start by reading how to choose your first roleplaying game. And once you are ready to begin, see what your game asks for: the right dice, or a starter box that has it all inside. Then you need not worry about the rest.