Jeff's will usaully have a few things to get signed. For the Prince Fielder signing you could have bought 8x10's, 16x20's, balls, and bats. I am sure he will have the same for Bill Hall. Just each thing costs different.
The signings are usually done at the Menomonee Falls stores. Here is their website www.jeffssports.com They will typically make the anouncment for a signing a couple week in advance, and then you typically have to by tickets for the signing.
Exactly, I don't care if I spend $25 on a Jenkins bobblehead and then its worth $1 in 3 years, because its something for my collection and hobby, and I would not resell it.