Price is guaranteed but the order executing at said price is not guaranteed if the stock is moving fast enough.
Price is not guaranteed but the order will execute regardless of how fast the stock is moving. If the stock is moving super fast the price can be way off.
Disclaimer: This information is only for educational purposes. Do not make any investment decisions based on the information in this article. Do you own due diligence or consult your financial professional before making any investment decision.