Trading is either zero-fee or a small fee depending on the trader's trading activity in the last 30 days. Trading fees have a distinction of a "maker" fee or a "taker" fee.
Maker fees are paid when you add liquidity to our order book by placing a limit order below the ticker price for buy, and above the ticker price for sell.
Taker fees are paid when you remove liquidity from our order book by placing any order that is executed against an order on the order book.
If you buy or sell using a market order, you will pay the taker fee because a market order immediately removes liquidity (other traders' offers) from the order book.
If you place a limit buy below the current market price, or a limit sell above the current market price, then you will pay the maker fee if the market moves into your limit order because you added liquidity to the order book, while other traders took your offer from the order book.
If the current market/ticker price is $2000 for 1 BTC and you market buy bitcoins starting at the market price of $2000, then you will pay the taker fee. In this instance, you have taken liquidity/coins from the order book.
If the current market/ticker price is $2000 for 1 BTC and you place a limit buy for bitcoins at $1995, then you will pay the maker fee IF the market/ticker price moves into your limit order at $1995.
A note about hidden orders: If you place a hidden order, you will always pay the taker fee. If you place a limit order that matches a hidden order, you will always pay the maker fee.
See the complete and current fee information on our Fees Schedule.