Today, Dungeons & Dragons are rule books. However, to a minimum, if you actually want to play D&D, you need to get a set of dice. One set is 7 dice of various sizes as described in detail here.
These sizes are:
1d4
1d6
1d8
1d10 (x2)
1d12
1d20
Today, a set generally includes two 1d10 dice. One for the units and one for the tenth. ...