I had bought a couple 'Sekka' from Brussel's Bonsai, Olive Branch Mississippi. Bought them in 2016. They were starter plants, maybe 1 inch diameter trunks for about $75 each. I would guess they were 10 years old or older, they were in 6 inch bulb pans. They were one of those things where they only had a few, at the back of a bench filled with more mundane trees.
In the USA they are around, and they are not very expensive for younger material. Older mature material can be pricey. Not having an accurate sense of scale from the photo I would say the tree pictured is good, but the price seems pretty high. If you like it, and that kind of money does not harm your dependants, go for it. It is true that Hinoki 'Sekka' is not a ''beginners'' tree. They are difficult to style and maintain. The horticulture is not difficult, but keeping foliage where you want it is a unique skill set.