does the question mean:
1. flashlights currently in possession?
2. or all flashlights bought at any time?
incandescents were expensive
comparing dollar values with
an inflation calculator.
I dont really know but I have 11 w30s
I’ve been tracking and its $437 USD for 20 lights (I live in China where the lights are cheaper). I’ve spend around $100 on other related items (batteries, chargers, illuminated switches, modding stuff).
That is 4 of them
Nah, the idea was first seeded when i started selling some old lights, then was helped by my family photo thread, then was nudged by the 5 lights thread, then helped along by my plan to spend the sale proceeds on new lights then was inspired by the SF11 being out of stock/new sofirn AA light being defective then the spend $2000 and save $524.93 brought it all into focus.
I plan to post my approximate cost once i am more awake since i had calculated it mentally in the 5 light thread.
Since Postimage is currently experiencing technical difficulties i can’t view the pics in my family photo thread.
However i have them on the phone hence was able to calculate it.
About $345 i spent on my current collection but some are won in giveaways.
About $45 in batteries
If you include giveaways and modding parts and losses on lights sold i am up to about $600-650 
The real question for me is, how much do I have into the lights I actually use. Probably about $250. I’ve still have around 60 lights I never use, and not sure I want to add it up.
How does it self fund?
I have a spreadsheet with all my flashlights and a grand total. I dare not share it with others in my family, especially my wife!
And for the last several years, I don’t include shipping costs with the costs of my flashlights. For one flashlight, there can be several shipping costs, like for the host, driver, LEDs, and battery. Now I just track the part costs.
But how’s that any different than my daughter tracking how much she spends on Starbucks? The total cost should also include the cost of driving to the locations, parking costs, tips, etc.
Regardless, I know I’ve spent too much on flashlights, but I’m OK with that since it’s my hobby and I can afford it. And I feel like I’ve been somewhat reserved since there are so many other flashlights that I choose not to buy.
Definitely thousands. I just put together a spreadsheet as well.
Never calculate it (yet).
I don’t even know the exact number of flashlights in my possession but it’s not that much either.
I have about 350 lights. I think I’ve spend 15000 to 20000 Euros.
Robert
I just started buying flashlights during the Lunar New Year last February, because Nitecore Singapore offered an interesting discount of S$47 (US$35) per order above S$79. I bought two package bundles of MH12S, and MH25S.
My “addiction” to flashlights began when I discovered Sofirn, Wurkkos, Astrolux, and Convoy on Banggood and Ali Express.
In less than 10 months, I must have spent about US$2,000 (based on my wife’s claim/estimate of US$4,000).
In fact, just a few minutes ago, I landed another interesting buy: Wurkkos DL70 with two 26650 cells on Ali Express for just S$67.27 (US$50), because of the ending 11/11 and extra 10% discount for Wurkkos “fan”. 
How do you decide to buy a light?
By price, features, combination, other specs?
Since pretty much everything I buy for this hobby is online I could probably go back through purchase history and calculate it but ‘aarrhh’ what pain in the butt that would be. It would suck the fun out of my hobby 
Fun is in the eye of the beholder
Why haven’t you made one with all 11? Do you have access to a 3d printer? Should be a fairly easy design and print.
Good question for this Budget Light Forum. 
.
Just flashlights…….$1,000 to $2,000.
Flashlight modding parts……$1,000 plus.
Accessory tools and supplies for modding…….$1,000 plus.
Lumen tubes, light meters, batteries…….$1,000 plus.
.
I do not have many lights because most of them are purchased for modding, its fun to own a “one of a kind” 
Ordered some parts for a scratch build at $100 and I will need another $200 min to finish it.
It is fun to take a $150 light and make it outshine one costing $400.
I am on a budget, other members spend many times more than this.
.
Bort, usually my first criterion is based on good reviews of a particular flashlight. Then, the second criterion is a good discount. The third is a flashlight that I don’t have, from a reliable brand and seller. Lastly, the price is reasonable and within my spending limit for the month.
As of 10.9.2017 for Everything….
Lights=$3800
Chargers=$300
Batteries/ Vol.Meters=$1500
Total=$5600
From then to now…Add this
Batteries=$455
Lights=$1460
Chargers=$150
Grand total=$7665 
Give or take $150
All of these are used…NO shelf Queens. Some of the older ones not as much. But still used.
P.S. Started hobby in 2011.