Tony Hawk Skateboard

I have an Alien Workshop Skateboard that was skated quite a bit before it was signed but has been sitting in my garage ever since. It was autographed at a skate park that he part owned with Dave Mirra in Wilmington, NC around 6-8 years ago. I was just wondering how much it is worth. I also have a Tony Hawk Flying Falcon T-shirt that he and his son Riley Hawk autographed when Riley was 5-6. I also got Matt Hoffman to sign a dollar bill because I was running out of stuff to get autographed. Thanks in advance.
Corey