There are two ways to buy or sell cryptocurrency using the BuyCoins API.
Buying from and selling to BuyCoins directly.
You can specify the exact price at which you want to buy or sell a cryptocurrency.
Limit orders may take a while to be fulfilled because there might not be a user that wants to engage your order at your specified price for a while.
Your order is fulfilled near-instantly.
You are unable to specify a price at which you want to buy/sell a cryptocurrency.