BXT-GRAVEL-135 prize differences

[Bimmerbernd]

Hi people of Chinertown,
did anyone coming from Europe purchase the BXT-GRAVEL-135 frame lately? I found large price differences between different offers including shipping.
The offer on ebay is 379€ incl. shipping.
https://www.ebay.com/itm/157080930219
On Ali it's 513€
https://www.aliexpress.com/item/1005004622346065.html
And on the BXT shop it's ~440€.
https://bxtbikes.com/products/carbon-gravel-bike-frame-road-bicycle-frame-disc-brake-internal-cable-27-5er-thru-axle-new-2024?variant=49606734282999

Why the difference? I guess taxes are not included in the ebay prize?
What would be the the best and most reliable source?