I make my casts from plaster - which is pretty heavy for a piece this size and the UK postal charges aren't cheap. Sending to the US would probably make a purchase out of the question (depending, of course, on (A) how loaded you are, or (B) how much you'd like to own one of my forts!).
I can research postage costs to the US, but I doubt the price would be attractive. You can see I'm really selling it!
It is a great terrain item, with loads of detail. It took ages to make and a cast of it is well worth owning and a pleasure to paint. I designed it with gaming in mind, so minis have lots of space to move on the stairs and walls as well as inside the fort. Talk about limited editions! I have one, I sold another on eBay, Tim has one and Jack has one. So, it's not a boringly mass produced item but something 'a bit special'!
I'm not going to make a million selling this one! However, I like the thought that I've sold some and that the owners are well pleased with them. That's cool.
In the future, I may make some smaller terrain pieces which will be far cheaper to send and therefore widen the potential market. We shall see. At the moment I've got my work cut out sculpting my dragon - and he's moving at a bit of a snail's pace (because I have a family and a job!).