Hey Bram, this is always a tricky one but you have had some sound advice here already.
Is the figure just a loose figure? DT luke or something? In any case, as long as the figure is well protected in transit you should have no real concerns about it getting damaged.
If the figure is unlikely to get damaged then all you need to do is make sure it arrives so definitely use a very good tracking service. It is worth the peace of mind. If you definitely trust the seller then I woulnt pay for insurance to the value of the item as this will get you clobbered with customs fees like Andy says.
I do pay for insurance when getting fragile items shipped as I am paranoid about them getting damaged in transit. However, despite this I think you have to go a long way to prove that the postal service damaged your item. Especially on international shipping. Both countries will more than likely plead ignorance and you would end up shafted IMO. If a figure were to burst through a bubble for example whilst in transit then you would be hard pushed to pin the blame on the postal service as there may not be any physical damage to the box itself.
I guess my advice would be, if you trust the seller; get him to ship it with a trackable service but to mark the value down. If he is a board member then he will have his reputation at stake which is normally an incentive to get the deal right. (99% of the time)
Im sure it will be fine buddy. I look forward to seeing what it is!
Chris. 8)