The rate of a 300 USD Amazon gift card today can vary depending on various factors. One of the main aspects that influence the rate is the current market conditions. If there is high demand for Amazon gift cards, the rate might be more favorable.

Typically, the rate is determined by the exchange value in the secondary market. Sellers might offer different rates based on their own assessment of the card's worth. Some might offer it at a rate close to its face value, while others could have a slightly discounted or inflated rate.

It's important to research and compare different sources when looking for the rate of a 300 USD Amazon gift card today. This could involve checking online platforms, marketplaces, or even asking around in relevant communities to get the most accurate and beneficial rate for your purchase or sale.