Is there a site that can give me the official (or close to it) value of sports cards?

Question

Just found my old hockey and baseball card collection from when I was nine or ten.I'm considering I can use it as an investment for retirement.

Answer 1

I think there is a difference between list value and what people will pay. If you want to know what people will pay, join EBay and do a search on each card, checking the "completed items" box in the left column. It shows sales that have already been made and what the final price was.