Size 241*125*65mm, Input voltage 90-132VAC/180-264VAC, Adjustable ±10%, Voltage 70V, Model S-800-70V (Custom Edition), Power 800W.
You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
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 coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($76.50): hoNEYbGdeAlS
2. ($78.16): BG00c906
apply code in your basket (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): bGhOnEy10, BG70V, BGS70V, BgcLuBofErtA10, BG53PSU, BGCLUBOFERTA10, BGAFF10OFF, BGCuponation10, BG59PSU, BGHONEY2110, 13f142, BG4742c4, ADMITAD2212, Terence, Tabby20, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for RD6012 RD6012W S-800-70V 11.4A Switching Power Supply. The lowest price was: $39.99.
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)).