Welcome to the forum. Your first question is too subjective to arrive at a definitive answer. It depends on a variety of factors. Overall condition - which is impossible to adequately assess over the internet, especially with so little known about the engine in question...and your location which is also unknown at this point. Basically, its whatever someone is willing to pay. Couple hundred bucks probably. IH drivetrains outlive their sheetmetal enclosures by a wide ratio, so there really is no shortage of donor engines, transmissions, and axles to be had.
Your second question is much easier. IH Parts America, the vendor which makes this forum tick, has most everything you need to get your Scout tip top again. They have many items displayed in their web store, plus a great many others not shown which can be ordered over the phone.
This forum houses a wealth of valuable information for the IH enthusiast. I urge you to take some time and browse through the various sections. By doing so, you'll find the answers to a great many of your questions without ever needing to ask.