Aliexpress
Click here… to search for 16 pcs. Vacuum Cleaner Parts Roborock S50 S51 S5 MAX S6 1S [EU] on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Europe 
. There’s only 1 record in my database, so I have no idea if the price is OK. You can get coupon down below.
Link: Banggood product page
Coupon (22.61 USD): BGAHPU13
(CouponsFromChina.com tip: this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG16PCSES, BGHOMEA13, 13f142, BG10OFFAFF, BGEFDRSV, BGwhielabel, BG10OFFAFF1, BGe99602, BGd4fb13, 00c906, BGPT0127, BG00c906, BGJUNEGSG9, Cuponation9
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
There is only one database record (it was for 18.99 USD), so you can’t see price history chart.
You can set price alert (for Banggood).