Price history, coupons and price alert are available on this page. What is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Wireless Standard: IEEE 802.11 b/g/n 2.4GHz, Enclosure Material: ABS V0;, Max Power: 2200W;, 433.92MHZ;, Power Supply: AC 100-240V;, Max Current: 10A;, Gang: 1;, Product Dimensions: 91*43*25(mm);
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
1. ($17.18): ADMITAD2212
coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): elec, BG15Gadgets, SONOFF15, bGpAnDacHeCk, BGVDay10%off, bGhOnEy10, BGSMOFF, BGSONOFF15, BGELIG0920, 13f142, BgcLuBofErtA10, BGSONOFF16, BGAFF10OFF, BGSTHO15, BGCuponation10, BGHONEY2110, BGSHOM15, BGSHE15, 6GSGIT, BG15Sonoff
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF RF R3 Smart Switch [EU/UK] ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for SONOFF RF R3 Smart Switch? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
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)).