Are you new to civil war reenacting?  If so you can definitely find a lot of good items in the militaria +civil war+reproduction items area of collectables on EBAY.  Look for used but not worn out items that will immediately help you to look like a "veteran" instead of all new items that say "fresh fish".  Be sure to follow the authenticity guidelines of your chosen unit and keep your impression, union, confederate, or even civilian generic as possible. This will allow you to fit in immmediately into many event scenarios as you continue to research your impression.  Eventually with much more research you can then refine your impression to a more specific look or even an actual historical personality.  Most of all... Have Fun.