I’m a novice collector just getting started. Saw some really cool aviation autographs on University Archives auction coming up. They had how/low bids for R. E. Byrd TLS Ahead of 1927 Orteig Prize Attempt & Trans-Atlantic Flight, Earhart, Eddie Rickenbacker,  Doolittle, Turner, Sikorsky, and Roscoe Turner & Fred Hawks. Any idea how high to bid? I imagine the Earhart will be out of my reach but the Byrd and others have no bids! (Yet). Thanks!