Welcome Easy,
Agree with all of the above, except when it comes to the level of cleaning done by some of the ebay vendors from whom I've bought. Coopersark's offerings have been spectacularly clean. You can find the occasional good buy on Ebay, but not all that often, and you need to be willing to either do the restoration work, or pay to have it done. Most of the pipes that I've bought on ebay have needed to be thoroughly cleaned.
I've occasionally seen much better deals with on line dealers than I've seen with ebay. While there can be a much wider array of pipes from which to choose on ebay, there is also a much larger body of potential buyers watching them. I've witnessed many auctions where the price has spiraled way above any semblance of sanity because two or three overly enthusiastic (or determined) bidders got into a dogfight over a pipe. Getting 2-3 times a normal market price for a pipe may be great for the seller, but not much of a "win", in my book, for the buyer.
Before bidding on ebay, spend six months watching auctions. Save auctions on pipes that you may want to buy. Study the pictures, ask questions of the sellers, note the results, look at the bid history, but don't buy. Get a sense of the market for different makes that interest you, what shapes and finishes go for higher prices, etc. If you're going to buy on ebay, know what you're doing. Then buy and get surprised with all of the unexpected things that can accompany that purchase. Don't get invested in "winning" a pipe. Walk away if the price goes too far north. Another opportunity will come along. Never bid on a "no return" auction. It doesn't matter how good the pictures are, or the seller's description. Nothing takes the place of being able to hold the pipe in you hands and studying it.
You can do well with ebay, but it's not for beginners. On line dealers and B&M's are a safer way to go.