What to do?

So I'm kinda stuck right now. I know it's pretty essential that I obtain the service manual for this bike. Much of the technical information like the valve timing, fluid information, carburetor adjustments, etc are in the service manual and its vital that I know that information. Well after hours of looking around my farm and my fathers old shop that he used when he was racing, I still could not find this manual;  I then resorted to the internet. I couldn't find any online copies, but when I searched Ebay I found one. The manual I found on ebay is exactly what I need, a 1975 MX2 125-250 service manual. The only reason why I'm hesitating on buying this manual is that it's $50! Is it worth the price? Do I have any alternatives? I'm gonna sleep on it.
Thanks for reading!
-Cody