Keep an eye on ebay and other forums, I got a spare pair of the lightweight purpose built german model for not a lot of cash, less than £20 posted
I also made my own pair (before getting the lighter german shoes) mostly out of aluminium channel.
A doddle to make really, here's a few pics to give you an idea, they work great, tywraps or jubilee clamps will keep any deer/boar leg on the aft channel and they are fully adjustable and really easy to walk in.
You get the idea anyway
Hope that helps
Rb