Here is a quote from investopedia about how to make the order as market making:

Let's take an example of a stock with a bid price of 25.25 and an ask price of 25.26. If you offer to sell (or short sell) at 25.26 and wait to get filled, you will have provided liquidity and will be credited on many ECNs. On the other hand, if you sell (or short sell) with a market order at 25.25 you will be charged or debited an additional fee on many ECNs because you have removed liquidity. The same works for the bid - if you bid at 25.25 and wait to get filled, you will be credited; if you market buy at 25.26 you are removing liquidity and will be debited. The debit for removing liquidity is almost always more than the credit for providing liquidity.

http://www.investopedia.com/articles/trading/09/ecn-credits.asp

 

From what I understand, this means that we should know the bid/ask prices (which we don't have). Is there any way else to do this? one method could be adding/deducting a cent to/from the limit price. But it may not be reliable.

Any other ideas? Thanks!