Aliexpress
Click here… to search for Skydroid T12 RC Transmitter with R12 on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (363.40 USD): Parts8
(CouponsFromChina.com tip: put item in your cart and apply coupon code there 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): 502C6B, BGCITYADS2019, BGVDay10%off, BGTT10, BGSKYT12, bGhOnEy10, BGSS10%SW, bgshOOp10, BGRC902, 7bcdf9, BGRCRR9, BGCuponation10, BGDAVIS, BGradio9
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for Skydroid T12 RC Transmitter with R12.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).