The rate of a $15 Google Play card can vary depending on several factors. In the current market, it might not always be a straightforward one-to-one exchange in terms of traditional currency value.

Some platforms or individuals might offer the $15 Google Play card at a discounted rate. This could be due to various reasons such as promotional offers, bulk purchases, or to attract more customers. For example, a person might be willing to sell it for around $13 in certain circumstances, which provides a potential savings for the buyer.
On the other hand, there are also instances where the rate could be slightly above the face value. Maybe due to scarcity in a particular area or high demand for Google Play services. So, it's important for consumers to keep an eye on the market trends and different sources to get the best deal when it comes to obtaining a $15 Google Play card at the most favorable rate.