First Time Buyer-Real Estate Broker Commission?

[Ryan D]

I am a new investor about to buy my first property. I never signed a contract with an agent, but have been working with one for several months. Seeing as he is a "buyers" agent I was under the impression that he would split commissions with the sellers agent at closing. I am going over the sales contract and he is asking for a commission of 3% of the sales price from the seller. This is the first time he has talked about a specific number he will charge. Does this sound right? This will ultimately effect what I am able to purchase the property for right? This is my first property and I want to be sure he is not taking advantage of me.
Thanks!