As the title says - I want to buy a SOP. I'd prefer used since money is tight, and thought that checking Ebay or Amazon would be a good place to start. Woah - there's 1906 reprints, OCR scans, and who knows what else, and I"m so confused. My original understanding was that the APA would publish a new Standard every few years, and silly me thought I could just go on ebay and buy a 2000 edition or the like for a reasonable price. Asides from the Real McCoy from the APA store, are any of these editions worth buying?