Explain something to me like I'm retarded
Yesterday, a certain stock was worth $17,70. I thought it'd fall to around $16,20, so I bought 600 put options at 0,75 each.
Today, the stock has plummeted. In the morning, while it was worth around $16,50, the options were worth $1,10. Now, the stock is worth $16,10 and the options are $1.
Why is it that the options' price fell? When buying them, should I aim for the lowest reasonable price possible? Why?