It depends. We're getting anywhere from $120 to $130 over the exchanged listed prices currently, so you might do better by avoiding the brokers at this point in time. I have both coins and kilogram bars and have no problems with selling or buying either, though I have a lot more in kilos than coins these days. I also keep good records of sales and purchases, and keep my averaged prices both for my total mounts, and my recipients are valid and help out a lot when selling and buying the kilos, which have serial numbers on them from the smelter wholesalers; that way I avoid any IRS hassles over how long I've held a given lot. I get audited often anyway, due to filing W-2g's every year for both me and my wife, so it's a habit now and not much of a hassle any more. as an aside Mexican Gold Pesos are hot now; they're high quality and popular with collectors.
Unless you live in Namibia or Cairo on Thailand or something, fraud is actually pretty rare among American dealers, as they tend to know each other and their customers pretty well. Different story with the gold paper peddlers and some of the penny stock mining companies.