I've gotten lucky at a few, but most of the time the single coins - morgans, etc. are going for well over market price. I saw a very old woman and her daughter buying casino Silver Strikes last month at $40 each. All were common, I even had a few (two I won at the casino, a few others I picked up cheap along the way). You have to be selective. I've done really well in the "pile of foreign coins" department, and in the ability to grade on the fly. I picked up a 1905-P Barber Half in uncirculated condition in a pile of what were called "dirty old silver coins in pretty good condition" according to the auction listing. PCGS graded Uncirculated / env. damage details. I sold it for a HUGE windfall. Nobody took the time to examine the coins and were all paying melt price in apathy. I also scored some uncirculated quarters, and a 1934-S in VF or better in a pile of "morgans and peace dollars - circulated" that people again were paying melt price for. I recently picked up an 1888-S which should be arriving back from ANACS today that came in with a grade of MS63. I picked it up for $140 in what was listed at the auction company as "very good condition." Gotta thank them for providing a grade without realizing - and all the others that didn't take the time to examine the coin. Of the dozen morgans sold, this was the one to buy. I knew it because I examined each coin. Then there was the "second best" score ever. In a " pile of old foreign coins from Belgium" lot I picked up an uncirculated gold coin from Finland circa 1879. I paid $25 for the whole lot - and scored huge. I'm a treasure hunter by hobby, and I know how to test and grade coins pretty well. I'm no expert, but if you put the time in at the auctions and estate sales, you can do well. My absolute best score ever was an unopened bank bag from 1979 full of dollar coins (remember people going crazy over silver in 1979 added lots of speculation). I put together the details, did the research and spent a bit too much for a complete unknown, and after a couple years just sitting and staring at it - decided it was time to re-coup and move on. I had a guy that just kept insisting that it was silver and wanted to buy it. I never opened it, but I knew it weight 25.12lb on my digital scale. He didn't care, or he didn't understand and offered me a handsome profit for it. Some people just don't understand math. Happy Hunting!
Estate sales are the primary way I obtain coins. My experiences have been overwhelmingly positive, and prices are FAR below what "show circuit" dealers will sell for. Why? Because those very same dealers are at the very same auctions, buying inventory, and they seem to "require" a 100% markup in order to survive. Of course, the viability of this method can be VERY location-dependent. My area is just LOADED with decent auctions nearly weekly. (South-central Pennsylvania.) Auctions are so much a cultural way of life here that I can scarcely put it into words. Example: I drive 20 miles from my house to the city where I catch a train for the rest of my commute. In that car trip, I counted, just last week, 12 homes for sale by public auction on a fixed date, and only 4 with a realtor's sign out front. Such is the culture of auctions here - people here simply LOVE them, and so do I. The main ways to find them are the local "penny saver" weekly newspaper, and auctionzip.com, with a search for the word "coin" within 30 or 50 miles of my zip code. Then, I click on the dates that hit, and decide which of very many to attend.
I am actually talking about an actual "estate lot". One where the seller got them from an estate sale. I am not talking about those junk lots with a bunch of worthless coins, post cards, baseball cards, gold flakes, and junk jewelery. That is just a marketing gimmick like "unsearched rolls". Here is the lot I am talking about: http://www.ebay.com/itm/221704747074?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
That gold coin I got was in a "junk lot" at an estate auction. When you are looking on ebay, there's no telling where it came from or what they may or may not know. I guess that holds true for all auctions. The key to it is knowing what you are getting, and taking the time to really look at things. It's a gamble, but if you're careful they can pay off. On Ebay, I assume everyone knows exactly what they are selling and has a good idea of the value. It's possible to score a rarity in a lot, but it's "as the name implies" very rare. As for that lot you posted - it looks like they went for fair money. Maybe even a good deal. I didn't look at all the dates, but I saw some barber dimes and even a barber quarter in there. Highly collectible. Venture out to your local auction house someday. You might be amazed at what you find. We once came away with a 5 carat diamond tennis bracelet for less than the melt value of the gold. We had it cleaned and appraised and it covered our vacation! Then again we sold a rare $400 knife for $30 not knowing what it was. Mistakes are made, sometimes you get lucky - but with ebay - you should bet on a seller knowing exactly what they have. We only use ebay to sell off the "excess" from whatever treasures we bought. A lot of times we want one item in a lot - and ebay is a perfect place for that.
"THESE COINS AND NOTES WERE FOUND AT AN ESTATE SALE. YOU PROBABLY KNOW WHAT THEY ARE WORTH BETTER THAN I DO, SO I'LL START THE AUCTION OFF" <-- item description. This guy more than likely knows exactly what he has and who says they actually came from an estate sale to begin with? You can say whatever you want and no once can prove you wrong.