You need to define "best value" first. Is it simply cheapest, or do other things like robustness, reliability, beam shape, tint, CRI, UI, etc count, and if so, by what amount ?
No 'no name' brands.
I'd like to know if there is a basic order of magnitude rule with regards to output/cost.
Can you get a 100 lumen light for $10?
Will a 1,000 lumen right run you $100?
Who will sell a 10 kilo-lumen first? Will it be under $1,000?
An inexpensive quality 100 lumen light will be around $30, like the Illuminati.
An inexpensive quality 1000 lumen light will be around $150, like the Catapult.
An inexpensive 10000 lumen light would be a hand built Mag hotwire, so the quality would depend on your skill and investment, but you could probably pull it off for around $300.
Just got a chinese XML light for $28 shipped. Manufacturer's claimed output is 1200 lumens but in reality it is probably no more than 850-900. In any event, lumen ratings don't mean much as they tell you little to nothing about how the light performs. It can easily be shown that a 150 lumen light can be brighter (greater throw, higher lux reading) than one that has an output of 1750 lumens.