Negotiating agent's/broker's commission

[Christopher Wilken]

What is the current custom for the agent's and broker's commission (I will just refer to the agent's commission for simplicity), and what is the bottom end of the range for commissions? Listing agent's typically receive between 2% and 3%, correct? 

I expect that commissions can be negotiated down as the value of the property increases, but how low can commissions go? Is 1.5% possible?
I have heard that that buyer's agents may steer clients away from properties with a lower buyer's agent commission because their clients are looking at many properties at a similar price point, but this property would differ significantly for the buyer's agent with respect to its commission, creating a disincentive for the agent to present it to their client, in theory. In reality does this happen? 

Of course, I am planning to list a property and want to ensure that I am not overpaying in commissions. 

Thanks in advance for your views on the prevailing agents' commissions.