All of the comments above are good and you should follow them. I would add that before you bid, do a search of the coin you are considering buying. Page down the left column to "Show Only" and check the box for "Sold listings." Make sure when you put the coin description in the search field that you include a "grade" or condition from the listing that is as close to the coin grade or condition as you can glean from the pictures and description (this part is tricky). Then also search for the coin sale price for more than a grade or condition below: e.g., for a coin listed as "AU" search sold prices for a VF, or EF of the same coin. This will give you the recent prices that particular coin sold for on Ebay. This way, you have an idea of the market value of what you are bidding on and you have a better chance of not paying too much for that coin. Also, if you want to sell the coin, you have an idea of what you can get for it.
Exactly the same could be said of Heritage - and maybe more so because there are no returns! I've sold more on Ebay than I've purchased, but good stuff from reliable sellers does show up now and then. It's also possible to build relationships with Ebay Sellers that enable you to make arrangements off Ebay in the future - but that takes history and communication (it isn't a violation of ebay rules to establish a relationship for future purchases and sales - only to approach a buyer or seller about making a deal on a specific item that's listed now). Sometimes there are obvious ways to do that if you can find a dealer's own website.
Virtually every Ebay seller who also has a Web presence inflates prices a bit for Ebay - understandably - so that's another route.
More so with Heritage IMO since for Heritage there actually is a no return policy. There really is no such thing as no returns on eBay which many sellers don't realize. If a buyer wants to return something it is insanely easy to get eBay to force you to accept a return regardless of your listing setting
Have to agree with Dragon...if you are buying semi rare or rae coins, David Lawrence and Heritage are very good to deal with. Sometimes you pay a little more, but like my friend always said "buy once, cry once".
This is good general guidance, especially for coins of average quality for the grade, but should not be an un-waivering part of your decision-making process. Two coins of the same grade can be of very different quality . . . one being Premium Quality, and the other just barely escaping the DETAILS designation, and would be worth substantially different amounts than prices realized in prior sales.
good advice given here. I buy from Ebay sometimes, but always folks that have a long track record and very good feedback. I also try to buy from ones I have purchased from in the past. That way I have a pretty good idea what I'm dealing with. I also sell on Ebay, especially minimal value coins I find in roll hunting. You may also want to consider the buy and sell section here on Coin Talk. You can also list a "want to buy" I also like coin shows and once a year get to Long Beach show, where I spend the $ gained from my trades and roll hunting.
Hate to split hairs, or websites, but there's a world of difference between Heritage and David Lawrence. Heritage is buy beware (although they can be helpful when there is real issue - i.e., they're not unethical) and David Lawrence has a no questions asked return policy - and they mean it!
DLRC are a coin auction house/dealer. They're numismatists and coin geeks, first and foremost. In 2015, coins and currency formed 40% of Heritage's gross auction sales. The other 60% of their business had nothing to do with our hobby.
Not to give bad advice but I've bought coins that looked great on eBay and were a disappointment in hand and others that looked scratched and blurry in photos that (although I haven't slabbed them) look near perfect in hand. Treat eBay as you would Vegas, be prepared for a gamble, do research before starting.
That just happened to me, I was the only bidder for a rare coin on eBay that had very bad photos. I took a chance and won it and the coin in hand was much nicer than the photos. However, it don't always work out that way
If you want to negotiate a price from David Lawrence's stock -- I found them tight the first time, but more generous on subsequent purchases. And it may simply be the coin I negotiated the first time. I have scored some good deals on their weekly auctions. And there's no buyer fee.
Just like any other coin dealer. Form a relationship, let them know you intend to be a repeat customer, and they'll show you some love.