Mega Stones Location
Starter Mega Stones
You can get 4 Mega Stones in the early stages of the game, in Pallet Town after beating the seventh gym leader, prior to fighting in the Viridian City gym battle. The Stones are given to you by Professor Oak and are as follows:
Mewtwo Mega Stones
There are two Mewtwo Mega Stones that you can find in the Cerulean Cave. These are possibly the last Stones that you will collect, especially considering that you get these after defeating the Green Trainer who shows up after the game’s main story has finished.
This means that you can only get these stones after going through the Pokémon League, defeating the EliteFour, and Green Trainer. The Stones you get are:
Buy Mega Stones
As mentioned before, you can also buy Mega Stones from a salesman found wearing a Slowbro outfit in the Pokémon League Lobby. This salesman sells the Mega Stones for $30,000 each. The stones that you can buy are as follows: