What is the transaction fee for Bitrue?

Can you clarify the transaction fee policy for Bitrue? Are there different fees for different types of transactions, such as buying, selling, or withdrawing? Is there a flat fee or is it a percentage of the transaction amount? Additionally, does Bitrue offer any discounts or promotions for frequent traders? It would be helpful to have a concise overview of the fee structure so that users can make informed decisions when using the platform.