Does anyone have any suggestions for the cheapest & brightest headlamps , using size 18650 batteries
and where to buy them ?
Your help and replies would be appreciated.
Bunch of people on the forum have this:
D25L Rechargeable Headlamp 1000 Lumen 90 High CRI
https://sofirnlight.com/d25l-headlamp-lh351d-5000k-90-high-cri-p0192-s0088.html
Yes, get one of the D25 from Sofirn - they have them in good LED selection.
The UI is a bit meh but if you want power for the price it’s hard to beat.
For this D25L are there any BLF reviews from users/owners ?
Not much to say about it, its a good cheap headlamp. Some like the band some don’t. Its not state of the art but better than decent.
I saw it very recently but I worried they may have green tint. Sofirn Sp40 with 5000K LH351D has very green tint.
When you buy something so cheap, satisfaction can never be guaranteed, For working on a car or general purpose its fine. If I was a surgeon, I would never use it. I had an $100 Nitecore in the past and they were comparable. Does not say much for Nitecore.
If you read the description of D25L you will see very likely Barry will release D25L with 4000K LH351D. I think it will be the same price and no need to worry about green tint.
My concern is that Sofirn probably changed their 5000K LH351D stock recently as my FC11 5000K also has green tint. I will stay away from their 5000K LH351D light for a while.
LED’s with Green Tint . I don’t really care for that color. 
My mistake I forgot to list in my OP is that I want
a cooler tint , closer towards the 6500K range and headlamps that can use both 18650 and 21700 batteries.
Maybe this additional bit of info will help in the replies. Thanks to all of you who have replied so far. 
21700 complicates it a bit since the D10 and D25 are 18650 only. Boruit has some 21700 compatible models on Aliexpress though, but not the same form factor and a little more expensive. I have a D10 swapped to a sst40 5000k. Even with the stock driver i still get almost 1000 lumens out of it and good flood/throw.
I just posted in another thread that the HD20 is on sale on Wurkkos’ site for 28.99 or 32.99 with battery. I’m not sure if that meets your definition of cheap, but it’s plenty bright, takes a 21700 or 18650. However it is 5000K and one of the two emitters is the LH351d which you’ve stated you don’t like. I still thought I’d throw it out there since afaik there aren’t a lot of good cheap 21700 headlamps.
I have a couple of the D25S models. SST 40 emitter is nice & White.
I have Nitecores & other brands too.
For the money this one would be hard to beat IMO. I like it a lot. My “go to” headlamp at this point……
The headband is the weakest point, but it is not that bad. It works just fine. 
For the cheapest and brightest 18650 headlamp, I would still go with the Boruit D10 Headlamp. BLF review here: Boruit Headlamp Review D10 (aka. EHL0628) - King of the Budget Headlamps?
For less than $15 (BORUiT D10 XM-L2 LED Headlamp) and includes USB charging and a decent UI, it’s a bargain!
I like the Boruit D10 as well.
I got the one with a neutral tint.
I prefer warm white, but the Boruit D10 neutral white is very nice.
For a headlamp, a fancy UI would make no sense IMHO. When I use one it is to free both hands up while working on something, the more simple the UI the better. D25S or D25L are not going to impress anyone, but they are just super useful for very little cash.
These two suggested headlamps are about the same price-$15. Are there any known outright comparisons
between the Boruit D10 XM-L2 and the Sofirn D25-S dual SST40 , as to which of these two is the better ?
They are in the right price range—Cheap ! Forget the use of 18650 & 21700 batteries , just 18650 is OK
The Sofirn comes with a battery and is a bit more floody, plus battery life will be reduced. If you care about modding, the D25 is far less moddable than the D10. Otherwise both are good.
Oh , the Sofirn is floody. Do you have any idea of how much throw the D10 has ?
Which one has the cooler color ?
No, my main issue is double click goes to strobe. Why? Who needs shortcut to strobe on a headlamp? I would say the majority would highly prefer 2C -> Turbo/High. Makes no sense to have strobe on such an easily accessible shortcut.
Are there anymore suggestions about what cheap & bright headlamps are available and where to buy them 
I’m looking for the 6500K (CW) color—No green tints please. Any zoomies out there ?