I have just checked coupons. The lowest price I could get is 257.59 USD for DEDAKJ DH22-C1L-E Oxygen Concentrator (in Banggood). It is from EU warehouse.Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest price update (UTC time):
Banggood (257.59 USD)
Banggood warehouse is located in Europe 
. Good or bad price? I don’t want to misguide you about the price. I don’t know if it’s good, because I don’t have enough records in my database… You can use 2 active coupon codes for this product!
Link: Banggood product page
Price without coupon: 279.99 USD
Coupon (257.59 USD): BGSPRING8OFF
Coupon (257.59 USD): BGHONEYSP
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): BGNEWYEAR8, BGd7112a
(probably won’t work, but you can try them out)
Aliexpress
Click here… to search for DEDAKJ DH22-C1L-E Oxygen Concentrator [EU] on Aliexpress
Here are coupons that you can use.
Price history and price alert
There is only one database record (it was for 257.59 USD), so you can’t see price history chart.
You can set price alert (for Banggood).