Cinemasterpieces is one of a very few top tier dealers. If it isn't in stock, they will likely know how to find what you are looking for. You will pay top dollar, but you won't have to do any legwork, and you can be assured that the poster they provide will be genuine and at least condition 8 of 10. If this is the level of service you want, then this dealer is for you.
From there, you head down into the pile of auction sites, other dealers and ebay. At this point, you are trading a lower price against an increased risk. You need to know more about the paper the lower you head into the pile.
The next level down is the poster specialty auction houses. At this level, you are competing against the knowledgeable collectors as well as the dealers. There are bargains to be had, especially if you are willing to accept a lower condition item. The C7-10 items though are going to go for prices that rival the better dealers. I generally work with 4 auction sites, and find they follow a set order in quality and prices realized. At the top is Heritage. Generally high quality and highest winning bids. Next is emovieposter. Third is mpb.auctionand about equal to rich is movieposterexchange.
With all of the auction sites, you need to be patient. It may be months or years before they offer something you are looking for, so you need to collect in broad categories, say 80s comedies, or 50s monsters. If you are only looking for a few titles, I find you will get bored and stop attending.
When you drop below this level, you start running into fakes and reproductions. There are known pirates and you can find references to them here. There are general classes, so you need to know the terms like 'minty white' or 'hairy belt' or 'little stick man' for some posters. You need to be aware of exact sizes as pirated stuff may be a fraction of an inch off.
Once you are educated, you can finally head into the ebay jungle and have a fighting chance of coming back alive. Yes, I have gotten bargains on ebay, but I have also been burned by stuff being misrepresented in condition and once by a video poster that had been cropped and matted to hide the fact. Count on being burned at least a few times if you frequent ebay a lot. Put it down to the cost of finding that elusive bargain.
