There are many reasons why bitcoin and other coins price is where it is. When the price either directly or indirectly influence the marketcap the price either rises or fall like the current situation. These are factors that influence the price; source: Crypto Update

1. Demand for the coin:
 Where there is a well tilted balance between the supply of a coin to its demand, the price becomes Bearish. The higher the demand, the bigger the price..

2. Total Supply of the coin:
 When the supply of a coin is way higher than how much people want it, the price falls. Shit coins fall into this category.

3. Market Capitalization:
This refers to the worth of a coin or token; the total value of all coins mined. E.g. Bitcoin's Market Cap was 729billion the last time I checked..
The market cap moves with the price of the coin..

4. Circulating Supply:
This refers to the amount/part of coins out of the total supply. These number of coins are available for sale and the rest are locked or stored away in the blockchain.

NOTE: Total supply of coins ÷ the coin Market Cap =Price of the coin.