I am sure that Alex will chime in here, but from my perspective (working in the repair field for 35+ years) there are many times that a scope is not needed.  Scopes are great for looking at wave forms and signal tracing.  In most cases presented, the problem is usually a short circuit or damaged component.  There is no need for a scope here.  Use the right tools for the problem presented. Attempts to trace distortion in an audio circuit are times when a scope makes sense.  If you are planning on providing micro-soldering services, it is likely that scope won't be a necessary tool for your shop.  Having tools like the voltage insertion supply, a microscope and hot air station are necessary. If you plan on repairing audio or video equipment, than a scope will make sense.  Grow your tool inventory based upon what you intend to repair.

In my shop, I have audio and RF generators, capacitance and inductance meters etc.  But...  I have repaired all types of equipment over the years.  Start out with a focus on the types of repairs that you intend to provide.  No need for excessive parts stock either.  Your parts stock will increase with time as you branch out into other areas or as equipment changes.  Don't over buy on specialty parts.  You should have a good supply of common parts though.  The parts books that Alex stocks are a good start for surface mounted parts.

In reference to the data sheets: You will find that there are some common failure parts and that you will come to know the pinouts for those parts.  In most cases unless you are tracing a particular problem, the only pin that is important is pin 1 which is used to properly align the part on the board.  I keep a folder (and a binder for paper datasheets) handy for quick reference if I need it.  Most can be found online either directly or via a supplier like Digikey or Mouser.

I hope this helps,

Dan