Ah I see, I misread the question originally. The contract that seller has with the listing agent is between the seller and the listing agent, a buyer is not a party to that contract and as such has no influence over it. As a buyer you pay a price, that's all.
The contract between listing agent and the seller may specify that the agent will reduce their comission if they are getting both sides, or it may not. A listing agent may also be willing to reduce their comission to increase the "net gain" to the seller to make the deal go through, or they might not.
However as a buyer you just pay whatever price you want and hope your offer is accepted, weather you have a buyer's agent or not doesn't change this. - Mon Mar 16 2009, 13:58
As a buyer you do not pay comission to buyer's agent (unless the seller is a fsbo who refuses to pay comission) the buyers agent gets paid by the listing agent. Some people look at it as buyer paying though, since the buyer is the one footing the bill in the end. (of course, since seller doesn't get that many the seller looks at it as their loss, i.e. the seller pays) it's one of the more amusing debates about rel estate. - Mon Mar 16 2009, 13:50