I haven’t done it for years but I used to go to autograph shows to get signatures from baseball players. Here are some recollections from back then.
The nicest player I ever met was Frank Howard. A friend was a Senators fan so I got Howard to sign a picture I could give him. He wrote such a nice inscription that you would think Howard knew him.
I have seen many Hall of Fame members such as Aaron, Musial, Mays, Mantle, Williams (both Ted and Willie), Schmidt, Feller, and Stargell. I went to several big shows in Atlantic City. The first one was for the 11 living 500 home run hitters and it was the Altamont of card shows. Very disorganized and poorly. A buddy went with me to help me out and he said he thanked Mike Schmidt. Schmidt said “Thank you”. I guess it was bad for the players too.
Mickey Mantle was just there. Not nice, not mean, just present. I guess he had heard all of the stories and was bored. One time, there was a lady next to him with a chart crossing off how many things he had left to sign (3000, 2999, 2998…). At least back then, and probably still now, the fee you pay goes to the promoter, not the player. The player gets a fee based on how long they will sign or how many items they will sign.
Ted Williams gave you a large clear signature. He reminded me of Reagan. He had (I assume) dyed hair and looked younger than he was.
I saw Joe DiMaggio in Atlantic City. He looked much older than Williams. There was a board with a list several feet long of things DiMaggio wouldn’t sign including Marilyn Monroe items. He wouldn’t even sign The DiMaggio Albums (a two-book set he had authorized).
I saw Bob Feller once. He had to stand in the line for coffee like everyone else. The promoters could have done better and had someone bring it to him. I’m sure he was in his 70s at least.
If you’re looking for things that appreciate in value (which wasn’t my main goal), I recommend limited editions. You don’t know how many baseballs a person has signed. With limited editions, you know how many there are. I recommend Perez-Steele art and Gateway Stamp Company envelopes.