A lot of posters (and the majority of new posters) are interested in buying coins from e-bay, but when you look, you are confronted with so many listings, many of which are from non-US sources, it's difficult to process. Could someone either recommend sellers that are mostly reliable and sellers that are mostly unreliable.
For the latter, you could consult the "Notorious Fake Sellers List" at forumancientcoins.com. See http://www.forumancientcoins.com/board/index.php?topic=18502.0, last updated in March of this year.
I've found that a majority of the obvious fake (regular)sellers on eBay are from outside of the U.S. As such, if I'm browsing the site, I usually screen out International sellers by narrowing my search (using the side bar options) to 'N. American listings only'. Does that mean that I may miss out on the offerings from a few legit eBay sellers from Europe/the U.K.? Perhaps, but with current shipping issues, and the difficulty if needing to return, I'm o.k. with it. That's not to state that I haven't seen a fair amount of fake coins listed on the site from the U.S., but often they are usually a seller offering a single coin that is an obvious copy. There are a few (U.S.) bulk fake-sellers that I have identified, but often they are usually hit-and-run...After ripping off a few people, their feedback gets hit hard and their ruse is up. Established long time sellers prefer to protect their feedback, and so those are the ones I generally look for. I tend to stay away from 'buy it now' only sellers. I also tend to keep it to only a couple figures on any one coin. eBay is a good place for bottom dwellers (so-to-speak) that aren't too picky about condition, rather their interest is primarily in the coin type itself. Many of the (regular)sellers that start their auctions at 99c are legit. What's important to me is that they offer a lifetime authenticity guarantee and that they accept returns. Good pictures are also preferred. I want to be able to see the details. I've had to return a few coins that turned out to be copies from random sellers that had fuzzy/out of focus pictures. eBay's seller protection program is good for buyers. While fake coins seem somewhat rampant on the site, and eBay simply turns a blind eye in policing them, it is still against eBay's policy to knowingly sell a copy of a coin and not declare it so, claiming it as authentic. AFIAK, it is also against Federal law as well. I suggest reading a few tutorials on how to spot fake ancient coins. Most have tell-tale giveaways, however some can be very convincing and even trick the most experienced dealers/collectors.
Also: one has to be careful not only of fakes, but of wildly overpriced genuine coins. Slabbed and otherwise.
There's so much garbage on eBay, i generally stick to a handful of sellers i trust: - Savoca-coins - Dionysos Numismatik - Numis_corner - Numismatiklanz Don't buy from highrating_lowprice aka Ilya Zlobin. As discussed in many threads, his coins are genuine; but his prices are massively inflated then "discounted" to a still-too-high price (In my country, it's illegal to advertise a discount when the items were never available at the higher price). He accepts offers, but his attitude seems to be "i'll rip you off if i can get away with it, but settle for a reasonable price if i can't". Just don't buy from him. There are better dealers more deserving of your business and you don't need a coin so badly that your only option is to buy from him.
With Lanz you have to be aware that they have a very casual approach to their philosophy on tooled coins and also occasionally let slip a fake…there are several topics on this already.
I have enjoyed some auctions with Savoca this last week. They have a wide selection and you can grab some lesser coins for under ten bucks. One word of advice, Savoca is in Germany and they charge a 16 dollar shipping fee, so it’s better to buy a few coins (which keeps the shipping from jacking up your price per coin by too much). You can buy coins over a week long period and then ask them to combine shipping on all of your wins. They will send you one invoice.
You could look for sellers on ebay who also sell on VCoins, like Lucernae; I've dealt with lots of VCoins sellers and was happy with all but one of them -- a seller who was located in Belgium, but the coin I ordered arrived in pieces, taped directly to the inside of a barely-padded envelope mailed from Bulgaria. It wasn't even in a coin flip. But even he gave me a refund without hesitation. Sometimes sellers charge different prices for the same coin for sale on ebay and on vcoins, I assume because of the different fees they have to pay. Keep in mind that if you're a buyer in the USA, ebay automatically adds sales tax. VCoins does not.
Great responses. I'll respond separately to some, but these are helpful, particularly the responses about non-US sources which are good, but the shipping is high ($25 to ship a $10 coin). I'll try and make a list of "The Good, The Bad and The Ugly".
I hate to exclude foreign sellers, but I agree, I am not comfortable with many of them. I admit to being a bottom dweller without much focus on my ancients other than "That's cool". Sometimes I'm OK at spotting fakes, but sometimes not so good. I notice that a lot of the shadier sites have "Private Transaction" or some such.
I will also point out that I sell coins on eBay, although I don't know if anyone on this list has ever bought any from me.