There are two separate trade interfaces offered by Coinmate; a “quick buy/sell” which is just really a market order interface which shows the best available price from the order book in a big blue bubble. Clients simply enter the amount they wish to buy/sell, and hit confirm, to have their account credited with the corresponding bitcoin.
Depending on the amount of bitcoin desired, the prices change according to supply in the order book. Coinmate trades in BTC/EURO. Coinmate makes use of the maker/taker trading model where orders that give liquidity to the market (makers) get a lower trading fee (0.05%) than those which reduce the liquidity of the market (takers) with a fee (0.35%).