At first guess it was around 30 USD from what he told me. As the other TECT's I own are small compared to it, so maybe around 10 USD. But remember that was a raw guess. There is a lot of small parts in that kit and he's to cover his costs of making a mold etc.
Great work Sam, hope to get mine looking as good when I get my airbrush/work desk etc. God I hate moving house, not doing that again unless I have to.