Contract with broker for 6 months - Anything to lookout for?

[Frank S.]

I've been looking for a commercial investment property for some time now with no luck. The numbers are just not good enough to make a deal work. So I decided to contact a broker in my area to help me search for a property. Found him on a LoopNet ad. Seems like a nice and legitimate broker. He says he will only work with me if I sign a 6-month contract with him. He went on to say I could give him a week's notice to cancel the contract. I believe this is normal but I'm not sure. Any thoughts on single representation contracts?