You can negotiate with your mortgage broker on fees, interest rates and programs. A mortgage broker receives a commission based on how much a bank is willing to buy a loan from his company for – either it is a percentage or a flat fee. Sometimes the mortgage broker makes enough commission to pay for all of your closing costs and still net a solid payment. The best way to make this work for you is to let banks compete for your business. Work with more than one mortgage broker and play them against each other. This may be a little awkward if you're not used to doing it, but if you focus on getting the best deal possible, it can work.