To state the obvious: there are only two things that affect price, assuming knowledgeable buyers and sellers: supply and demand. As you suggest, Ricky Jays Cards as Weapons is not rare by any means, yet it still commands a fairly high price. The reason? Demand. But note that the price of Jays book is now gently floating downward. Why? Because the people who would buy it at $300 all have their copies. And after the people who are willing to pay $200/copy get theirs, then the price will fall again. Ultimately, I think the price of this book will level off at $35-$50 in the next few years or less. There are just too many copies out there for the high prices to be sustained in the long run, assuming no other group of collectors starts to collect Jays book.
The same goes for the Tamariz books, although I believe the print runs on those books were far less than Jays book.
Lets revisit a key assumption: knowledgeable buyers and sellers. Not all buyers and sellers are knowledgeable, meaning that not all of them have good knowledge of rarity and/or where other copies may be purchased (aka, the market), a point Bill made about buyers (although it applies to sellers as well, I think). Ignorance isnt automatically a bad thing, as were all ignorant when we begin collecting, performing, etc. Thats one of the reasons why its important for a beginner to associate himself with more experienced folks, so he can get advice, etc. But not all people pay high prices because they are ignorant. Some pay high prices for convenience. They simply dont want to be bothered with hunting down a title that they seek. Thats why dealers make money. Dealers do the hard work of finding the books, and we have to pay for those services. And before you criticize a dealer for charging outrageous prices, ask him how many books he has in stock that havent sold in several years. Most well established dealers have many hundreds, usually thousands, of books that dont sell all that well. Just ask em, and I think theyll tell you that for every book they can sell easily, they have 10 books that they cant sell so easily.
As to sellers (including some who consider themselves dealers), many often confuse high price with rarity. The two have nothing to do with one another in the abstract, although practically speaking, most rare books do sell for higher prices. And old doesnt mean valuable either. One can find books printed in the 1600s for a couple hundred dollars each, even though perhaps less than a few dozen copies exist of such titles in the world. Why? Because nobody wants to collect those books. When I was 11 years old, I wrote my first book. I produced ten copies of it and gave it to friends and family. So copies of this little monograph are extremely rare. But Id be surprised if many people really want to know the thoughts of an 11 year old on alchemy and Christianity, and so if someone offered a copy on eBay, even though very rare, Id be surprised if it sold for more than a few bucks. So rarity and price dont go hand in hand. If demand is not there for a rare book, then it doesnt matter if its rare or not: it wont sell at a high price.
Im sorry for not answering your key question by providing prices, but if you see 5 copies of the same book sell for similar prices on eBay within a reasonably short period of time (say, 6 months), then thats probably a good indication of the where the market is at, and you have your answer. The Tamariz and Jay books are good examples of the point. Ebay has its aberrations in price, but not, I think, when multiple sales are involved within a short period of time.
Hope this helps a bit, even if not encouraging.