Here's my 2¢.
Before you buy on eBay, do your research! I tell newbies not to buy anything initially, but to watch auctions for a couple of months. You will get an idea of the price range for the item of interest, not only for the make and model, but also for condition. Condition matters. When you have a good idea of the general market price you will know what is a reasonable maximum bid to make. Your best defense against being screwed is to be informed.
If you aren't satisfied with the presentation, contact the seller and ask for more information, whether it's better pictures, or more info on the item. For example, I want to see pictures of the rim, the chamber, and the bit. If I don't have clear pictures of those parts of the pipe, I don't bid. If the seller isn't wiling or interested in responding to my requests, I pass on that auction.
If the auction is a "no return" auction, don't bid. Regardless of the claims of sellers, pictures are not enough. You need to hold the pipe in your hand and check it out in person. Nobody's pictures are an acceptable substitute.
Have a firm idea regarding what you are willing to spend and stick to it. You may win some and lose others, but there are always more items coming up for sale every day. Never, never, never, get into a bidding war. The only winner is the seller. If someone wants the pipe more than you do, let them have it. There will be more. However, if you really don't care about the cost, then go ahead and pay 500% of market. It's your money.
There isn't much reason to bid early. Most of the action takes place in the last couple of seconds. Sniping is a common practice. While it once may have offered an advantage, so many people are engaged in it that the advantage really isn't there. I see clusters of last minute bids all the time. Most of the time, the final bid falls into the usual range for that item. Occasionally two snipers with the dumb idea of bidding extremely high collide in the monetary stratosphere, which is great for the seller. If you have a bright idea, chances are someone else has it as well. If you have done your research and know the general market range you can avoid being roadkill.
Don't get emotionally involved, or let your ego drive your behavior. That is a good way to become roadkill. There will be something else to go after down the road. There is always more. Be patient.
If you are good at "reading" pictures, you may occasionally find a deal where less than stellar pictures, coupled with a significant opening bid requirement, result in a situation where nobody bids, except for you. An example of that happened for me last month. A seller posted pictures of a Barling Quaint that were not great, but were good enough for me to get a "read" on the condition. The opening bid was $350. I made the only bid and got the pipe for $350. It was in terrific condition with sharp carving, crisp nomenclature, and almost no wear anywhere. Properly presented, that pipe could have gone for twice the price and would have gone for over $1000 from a dealer. But those instances are as rare as hen's teeth.
There are some reputable sellers on eBay. Mwresche is one, Great Estate Pipes, ebuyer1932 (IRRC, can't remember the number after ebuyer), Treasurepipes, Coopersark, Briar Blues, and Pipestud are others and there are more whom I'm not remembering as I write this. They provide good pictures and descriptions, and they will honor their sales if there is a problem.
Don't go to eBay for great bargains. They do happen, but generally you pay what the market is at that moment. And the market may change. You are likely to spend more at this time of the year. People are thinking of getting themselves something special for Christmas and they bid more to get it. After the Holidays, people are staring with horror at their bills and are less likely to open their pocketbooks. Prices will be lower.
With eBay, always be prepared for the unexpected. There are so many ways to screw up a pipe, and many of them don't show up in pictures.
Don't blame eBay if you make a bad decision. They're not responsible for your foolishness. But they do offer remedies if you have a legitimate grievance and can't come to a satisfactory arrangement with the seller.
eBay doesn't exist to give you great deals. It exists to allow people to buy and sell. Period.
About "unsmoked" pipes. Unsmoked doesn't mean new. It means unsmoked. A 100 year old unsmoked pipe isn't necessarily going to look new. It's been in the attic, been bounced around in a few moves, or has been displayed on a rack so that the stem got horribly oxidized. Maybe a former owner liked to clench the pipe but never took a match to it, so there are teeth marks. Maybe a former owner dropped the pipe and never smoked it, but it has a couple of dents from being dropped. One of my unsmoked Barlings has clear evidence of light teeth chatter. BTW, this one wasn't sold as an unsmoked pipe. I could see that the pipe was in exceptional condition despite the middling quality pictures. I was shocked to see that it had never been fired up.
If you do your homework and become a knowledgeable bidder you can do well on eBay. If you're trying to get a steal deal you may be disappointed. If you get caught up in emotional bidding you will be roadkill.
