All it takes is one person to set the tone. To say what a particular coin will be worth.
For instance if I said, I have a 1 TB drive for sale and I will take 100 GRAs for it, then that sets the worth of the coin. From that point forward, anyone else who decided to hop on board and start selling would gauge the value of the item they are selling, on that first sale.
Right now, we gauge the price of GRA on the current value of BTC. When we should be trying to set our own value on it.
Once you do that, the price will then be more stable and increase as sales continue and investment opportunities arise.