3% is typical in DC - the commission from the seller is 6% and is typically split 50-50 between the listing agent and the selling agent (that's actually the buyer's agent). But there is no set commission rate for anywhere in the country. That's illegal.
I have to disagree with Vicky on an agent insisting that a buyer agree to pay a commission. To our agency, it's an act of desperation in trying to sign a client. Although that clause is written into all three area Buyer Agency Agreements (DC/MD/VA), we zero that area out because we will always get paid by the seller. The buyer should not have to pay their agent's commission. We only deal with agencies who are on the up-and-up and have it in the listing that the selling agent will be paid a commission. The commission is the commission, and trying to negotiate more than what is being offered on a sale from the buyer, because it's not written at what you expect to get paid, just doesn't fly.
When an agent shows a property, they know what commission is being offered because it is required to be part of the listing. However, I have come across at least one agent for a well known company in the Metro DC area who had 2.5% commission being offered, which would normally be 5% commission split 50-50. We found out at settlement she wrote her contract up for 6% commission, but only gave the selling agent 2.5% while she kept 3.5% for herself. That's not really fair, considering the buyer's agent usually has to do more work to get the contract to settlement and this house in particular only sat on the market for 2 weeks. But that's the cost of doing business for her, and it will cost her business in the future because when we see her name on a property we are less likely to work with her. I would never DREAM of asking my buyer to make up the difference on what I "should" have gotten.
If you're shopping for a property in the DC area, I'm licensed in DC, Maryland and Virginia and can help you no matter where you want to look. Feel free to contact me anytime.
Kangal Real Estate