Before something or an asset regardless of what it is can be traded, it needs a buyer, a seller and a marketplace. A marketplace is where you go to buy what you want. The cryptocurrency world has a marketplace where you can purchase and sell your crypto assets.

The buyer and the seller are the two basic entities in order for any successful trade to complete. Both parties help to keep prices of assets in check. When one of them trades excessively it can affect the price of an asset.
For example, if the seller sells too much, it can cause the price of an asset to reduce or decrease in value.