I have the very same model. I don't know what the go for 'in the wild', but I paid $169 for mine at Gander Mountain last year.
You might want to do a few searches on some of the web's competition shooting boards. These things always get bad reviews. I have no experience with others to compare them to, but they make an iritating 'clipping' noise during use. This is reported on every board I've came across.
I thought I could use them as an aid while hunting, but the noise starts to make me dizzy and nausias. The sound messes with your brain, and you have no percepion of distance.
They say there are brands that don't 'clip' out, but I've never researched them before. So I cannot recomend any.
I'm just giving you a little warning. Maybe you could ask around the COMPETITION forum here at ar15.com.
Good Luck