Let's assume one has a bunch of U.S. coins that they want to sell (pairing down their "collection", hopefully for a profit, of course). Ok, let's give it a number - say 500ish coins (plus about 3,000 Wheat Cents). Let's assume they all are relatively "low-value" coins (ranging from $0.01 to $299.00, but 80% are under $25.00 in value). If you had a large-ish lot of coins to unload, would you just go to your LCS and let them give you a price? Or, would you take the time to put on ebay to sell for hopefully a better price? Or, other options? I'm assuming that a coin show is NOT the right venue to bring this kind of stuff to. Are there Auction Houses that deal in these kinds of collections? What happens to silver that is sold "at melt value"? Does your LCS keep and resell most of that? Or, do those coins actually go somewhere to get melted? What would you do?
I would go the route of a dealer. Selling 500 coins on Ebay is a monumental and time consuming task. Not to mention the problems... the people that don't like them and want their money back. Trips to the post office. Lost shipments, etc.... My time is worth way more than that aggravation..... My guy sends melt stuff out the day he gets it because the charts move so dramatically.
Personally I sell coins on eBay as a hobby so I'd do that for most. Definitely eBay for anything foreign. Keep in mind a dealer is buying to resell it so he won't pay as much as someone who wants to keep it. I'd use a dealer for gold or silver you are selling for spot because eBay fees will erase your profit.
Separate the ones that are actually valuable (like that $300 range you mentioned) and do not lump them in with coins valued at a few cents. Those might be worth selling individually, or as a lump sum on whichever platform you prefer. The common date coins, ranging in values under a few bucks, lump them all in together and see what your LCS will offer. Then bring out the mid-range value coins (at that LCS) and see how he'd increase the offer. Just my personal thought process so take that into account. My LCS offers greysheet ask at a minimum (at least that's what he tells me after looking through his magazine for certain obscure coins sometimes) but he also takes into account the demand for those coins. Understandably so, as he's putting out his money to hold onto them until he can offload them. He does periodically hold ebay auctions (I can divulge his shop if anyone is interested) on items he wants to offload, and just starts a bunch of $0.99 auctions with no reserve and let it fly. I've lost out on a few of those auction items (never won a single one actually) but he does pretty well when he lists them on ebay.
Generally speaking, for the large bulk of lower value material, I'd say yeah, sell to a dealer. It's far easier than going the eBay route. You might want to individually sell the $100+ coins.