You can get 3.5 Inch for 44.84 USD with coupon (from Banggood). Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest coupon and price update (UTC):
Banggood (44.84 USD)
Banggood warehouse is located in China. There are no active coupons for this product, but the price is pretty low isn’t it? I think you want to know if the price is good. From what I can see this price is higher than average price (25.66 USD).
Link: Banggood product page
Price: 44.84 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGc355fc, BGb9c540, 8BGwbg2204, BG1ee527, tRaDetRaCKeR, pROMo8cuPoN, Cuponation9, BG8ReviTrage, BGcoupon8off, BGGutscheine, BG00c906, BG8OFFCOUPON, TTBLACK5, BG589b2e, BG892292, BG8FORMULAMX
(I don’t think these’re gonna work, but you can try ’em out anyway)
Aliexpress
There’re some similar items on Aliexpress in my database. There may be some other items though.
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
Waterproof Case 3.5 – 6.5inch | 2.13 USD | – |
 |
Ugreen Car Phone Holder 3.5-7 inch | 4.84 USD | Paste $2/6 coupon “STAND401” in the cart |
 |
Xiaomi Mija 13.5inch LCD Writing Tablet | 21.30 USD | – |
 |
Xiaomi Mija 13.5inch LCD Writing Tablet | 22.89 USD | – |
 |
Xiaomi Mijia 13.5inch Drawing Tablet | 23.65 USD | – |
 |
ORICO 3.5inch HDD Case SATA to USB 3.0 Adapter | 24.33 USD | Paste $3/3,01 coupon “2DN9OOJQ” in the cart |
 |
Xiaomi Mijia 13.5inch Drawing Tablet | 27.26 USD | – |
 |
Awapow 3.5 Inch Doorbell Peephole Viewer | 30.93 USD | – |
 |
Xiaomi Mija 13.5inch LCD Writing Tablet | 52.19 USD | – |
 |
ORICO Hard Drive Docking Station 2.5/3.5 Inch SATA to Type-C USB3.2 10Gbps Gen2 | 57.82 USD | Paste $3/49 coupon “ORICOVIP4” in the cart |
 |
XIANWEI 13.5 Inch 3K Portable Monitor QHD 3:2 IPS | 113.50 USD | – |
More on Aliexpress… Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for 3.5 Inch IPS TYPE-C Secondary Screen is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).