Gee that is a pretty stamp.
The bad news is that they wont ship outside the UK so if you are in the US, no go.
Order & Delivery - Inkylicious
Moreover, I dont see a single one in ebay or etsy in the US.
I jumped around to see if any US gen suppliers carry them, including The Stamp Room who carries a bunch of non US brands...no luck. A general search for them only brings up British stores that have them. They might be willing to ship to you though. But you are right, the postage is going to hurt.
I called my LSS because they carry some international-they dont have Inky, but she gave me two other stores to try in Boston and MD-neither have it either. But MD suggested you try Ebay.UK and Amazon. I tried Amazon and no luck and I cant get Ebay.UK to open for me.
Depending on how badly you want it:
a) email them and ask if they sell wholesale to anyone in the states
b) try a british store (google the name and stores come up) and see if they will ship here
c) watch ebay.uk
I know how it is when you really love a particular stamp. Sorry I couldnt do better for you.
Those suggestions Poppy are good subs though!