Estate sales take a bit of getting used to, yes.
First, as was said above, they are almost always run by a third party company. This one for Saturday, with its advertising and photos and marketing, surely is. So the owners won't be there, and neither will their family. So it won't have the sentimentality of a yard sale or garage sale, where you're haggling with the guy who bought this thing and treasured it and isn't so sure he want to sell it at all. Which is kinda nice to get away from all that personal stuff and just be pragmatic about buying the stuff you want without having to feel bad about it.
But that pragmatism goes both ways. This company selling this stuff knows what they are doing, and aren't very likely to just give stuff away. They will be doing their research on stuff all week, pricing it and organizing it and advertising, etc.. So you will sometimes see prices on stuff that is quite high (I've seen computers and such with like-new pricing, which is ridiculous), because the company will try to get as much as they can out of stuff, knowing that they can cut the prices later if necessary. But at the same time, these estate sellers are pragmatic most of all about one thing: they want all of this shit gone. They don't want to have to haul it away, or trash it, or anything. They want this place empty when it's all over, so they do tend to make some deals.
Of course, if you're after some particular thing that everyone else knows is there (like, say, a sweet blue SS Performer you've been dreaming about), then that changes things a bit. I suggest you be one of the first guys there, and haul ass (in a casual fashion, of course) directly to the backyard and to the grill to check it out. It'll prolly have a price tag on it, and you can see what you think. If you see a herd of Weberheads running in your direction, then claim that thing and sit on it. If you don't, then try to flag down one of the workers to either, a.) ask him to put a 'sold' sticker on it, or b.) tell him it needs a ton of work and you just don't know and can only offer him X for it (be prepared for him to tell you to take a hike). Or, c.) see that it's already got a 'sold' sticker on it somehow.
(To avoid c.) if I were Bman, I'd see if I could find a way to make contact with the seller to see what they want for that grill. If it's reasonable, maybe you try to close the deal right then.)
Once you've (hopefully) got the grill with your 'sold' tag on it, it's time to go looking for other goodies. Any guy who can afford to live in that zipcode and with the good sense to buy the Cadillac of charcoal grills is gonna have some other good stuff around. I'd go to the kitchen first, because he prolly has some good cookware, grill tools, meat injectors, rib racks, etc. in there. Then check the garage or shed or basement or whatever for other stuff: the cover, a stash of charcoal, accessories, cast iron pans, extra LP tanks, etc.. Remember that estate sales happen generally because someone made an unexpected and/or sudden move to the nursing home or the great beyond, which means that they are leaving a lot of stuff behind, often in a hurry. But don't you feel bad, because you will be carrying the torch forward for another devoted Weber fan. I'm grateful for the guy who kept my Red K OT+ for me since the year I graduated from high school, and for the guy in the fancy neighborhood who took such good care of my black SS (I'm sure it wasn't him who was using the coal bin for a trash can in the garage).
Good luck B. I hope you can sleep this week. ;-)