I am familiar with Indiana laws about auto knives, and other nonsense laws like beer sales on Sunday. It's funny that I bought this one from a police officer.
Spring Assisted Knives - Blade HQ Here is a resource for Benchmade. I just bought an older, but as new in the box 9550 AFO full auto for $85. In the condition you described, I have seen them for $20-$50 depending on blade condition.