Don't walk in the dark @ $520K you can take a serious hit if you don't have someone in the RE business working for you. You can also negotiate the commisions on a buyer brokerage and can likely save yourself a percentage of the commisions if you negotiate that with the broker.

I buy homes for an investment group, they buy the homes sight unseen based soley on the information I give them, in turn I get a percentage of the profits when the home is rehabbed or sold so I have a serious vested interest in making sure they buy right.

You can do the same you can offer a 10% bonus for the difference between listing price and actual sales price with the broker, this works well because he/she truly has a vested interest in saving you money.

And always hire a lawyer to review anything you sign, a few hundred bucks can save you a ton of headaches that will cost you thousands to fix. My general rule of thumb is to invest at least 1/2% of the total cost of an investment on other professional advice. To date I've never been burned and when problems did arise(and they often do) I had someone to stick it to other than myself or partners.