This is the set I bought, 7 years ago. It’s held up fantastically. The tiles are a bit loud and bit small, but that is actually normal. The only complaint I have, if one can even call it that, is that its difficult to clean finger gunk from between the carvings, but that only accumulates across entire years.
https://www.amazon.com/Yellow-Mountain-Imports-Japanese-Mah-Jongg/dp/B003UU129U/
The way I see it, you’re just paying more for packaging and accessories.
Edit: Album contains three pics comparing height width and depth
When I bought my first riichi mahjong set back in around June/July, I didn't know where I might find a high quality set to play with. I searched on Amazon US and Yellow Mountain Imports had a good looking set that was priced around 64 USD. I bought it, and along with shipping + tax it came out to 80 USD.
I was happy with the tiles at first, but soon something stood out to me as odd. The YMI tiles which I had looked about the same size as regular Japanese mahjong tiles, but they felt...slightly smaller than one would expect. At the time I did not have a Japanese set to compare, so I dismissed the thought.
Then one day while I was visiting family back home in Shanghai, I decided to order the 竹 (also known as Take or Bamboo) riichi mahjong set which I had seen people recommend online. I looked around and found that Amazon JP (amazon.co.jp) had lots of sellers which shipped internationally. The set was priced around 4500 yen, and with shipping came out to 7271 yen (~68 USD).
When I got the tiles I was shocked to see how wonderfully sized they were. I don't know how to describe it but the Take tiles felt the perfect size in my hand. There's just something about the dimensions that felt right. I did a size comparison between the YMI tiles and the Take tiles and immediately saw the difference.
The YMI tiles were shorter and thinner by roughly 1mm
The listed dimensions for the YMI set was 25mm x 20mm x 16mm.
The listed dimensions for the Take set was 26mm x 19mm x 16mm.
BUT, as you can see from the pictures I linked, the YMI set is clearly shorter by 1mm, which is expected. But the Take set is still clearly wider, even if just by a thin margin. I reckon that the YMI set is probably around 18 - 18.5mm in width. The depth of the two tiles seems to be exactly the same at 16mm.
For those of you who are thinking of buying a riichi mahjong set online, keep this post in mind if you plan on buying the YMI set. Buying the Take set off of Amazon JP and having it shipped to the US will come out to around 85-90 USD, a bit more expensive than the YMI but the tiles are properly sized. The selection on Amazon JP is also wider.
Tiles
https://www.amazon.com/Yellow-Mountain-Imports-Japanese-Mah-Jongg/dp/B003UU129U/
Mat
https://www.amazon.com/Mahjong-mat-junk-japan/dp/B0017KHW3A
Total $140.54
Because I don't know where you live in Europe, you'll have to find out yourself regarding shipping and import duties. Even if it is from Amazon. Good luck. Stay safe.
This is the set I have and I'm pretty happy with it
Yellow Mountain Imports Japanese Riichi Mahjong Set - White and Yellow Standard Size Tiles with Black Vinyl Case - with East Wind Tile, Set of Betting Sticks, & Dice https://www.amazon.com/dp/B003UU129U/ref=cm_sw_r_apan_i_RRJVM5MCCSB6SHEZNRKZ?_encoding=UTF8&psc=1
It's a bit cheaper, though it's a different set, and looks like the dimensions aren't the same. If you're set on the AMOS feel free to ignore me, but I'm personally a fan of the yellow mountain set