4x HEPA Filter, 4x Main Brush, 8x Side Brush.
Go down and check coupons out. Remember to check price history if it is available. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Europe 
. I don’t really know if this price is reasonable, coz there’s no price history in my DB. I am tired of searching coupons, but I found one for you…
Link: Banggood product page
1. ($22.61): BGAHPU13
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG16PCSES, BGHOMEA13, 13f142, BG10OFFAFF, BGEFDRSV, BGwhielabel, BG10OFFAFF1, BGe99602, BGd4fb13, 00c906, BGPT0127, BG00c906, BGJUNEGSG9, Cuponation9
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
It doesn’t make sense to generate price history chart, because there is one price record which is: $18.99.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).