Was holding out for a cool deal on the legendary Noctua NH-D15 - and if it was the chromax black version even better! But after watching prices for all versions (classic and chromax) skyrocket overnight after July 1 I had little hope.
Then discovered PB Tech selling the single fan version for $141.31 plus $5.00 (approx) delivery nationwide. Obviosuly temps will be slightly above the 2 fan version, but still impressive and I can shop for another NF-A15 chromax fan to meet NH-D15 (two fan version) specs if required.
Current retail prices I've seen elsewhere for this model are near $170.00.
Luck!
I believe one fan runs just two degrees hotter. Given the price of an additional fan it may easily add up to more than the two fan version. The new Deepcool 620 for $85 seems like a promising alternative as a dual tower dual fan that outperforms the D15. Though it's not 100% black. https://www.ozbargain.com.au/node/710561