PT Mate doesn't offer this option at the moment. However, to calculate your final price, you can do the following: [Your Price]/0.975+0.3.\
PT Mate charges 2.25% and $0.30 per transaction. That means, there's a fixed amount of $0.30 plus 2.25% of what you're charging your client.
As an example: If you charge $100 for a product and you want to receive the full amount, you calculate it as follows: 100/0.975 + 0.3 = 102.86. So your product's price should be $102.86 in the app (instead of $100).