I guess each budget light should be well under a certain price for the functionality. Like a spot style light might be budget under 100$ , and a pocket light would be much less under 40$.
I have used the olight i5 with an EBL AA cell for almost 1 year , it was free but still if you can get it for under 30$ i think its the best budget light I have used so far, nothing from wal mart back in the days before amazon or even the mag lights where better IMO , it has become my only light for around the house , back yard ,under the hood , EDC pocket , road trip lights. Its very diffused so it more like a lantern and coveres a wide and full area .
The only other light I like for budget was the anker lc40 , BUT its gone up to 30 bucks, if you can get it under 25 its a great deal and its more of a spot beam , so you can use it for a bike light or spot light up to about 30 to 50 yards, its great versatile light and can even be a bit of a tactical light for cqb situations. Its also solid can take hundreds of legit drops. Also its tuned very well compared to the thousands of lights on the markets , it doesn't over heat or try to push too much power to sell a max lumen rating , they did a good job. It could use tweaks like a place to put an anti roll rubber or a reversed clip for a hat , and charge and use function .
On the Diy tip, I built an great light set up IMO ( and by built I just ordered some lights and make a battery pack) out of some amazon light pods like these
amazon light pod and mounted them with a metal go pro tripod 2 prong tip and a nut from home depot.
The light pods where about 36$ and I only have used 1 of them so say its cost is about 18 , the mount was about 25$ ( 11 for the actual aluminum handle bar clamp with the build in 3 prong go pro mount , Which I already had for my garmin head unit ) , and the battery packs where from jag35 at 8 bucks per for 14v 4ah packs that just needed to be wired up( they are sold out but its still super easy to source 9 cells from that site , he is even still selling some tenergy protected cells for 2 bucks a cell so you wouldnt even have to worry about a PCB/BMS ), oh and like 6 bucks for some connectors , but I already had those laying around for other projects so the actual cost of wire and connectors would be like 3$ .
Its a 2000 lumen light that draws like 1.5 amps estimated. Its been on my bike for about 7 months now and its so great . Im sure some of you guys could easily make a hand held version , there are a few styles of light pods on amazon that would make a powerful light for well under some of the prices that the name brands charge. My light will run off 3x 3.4v 18650s and you can easily increase the capacity with 3x3 or even 3x2x21700s at 5000mah for a 10ah light that would still be hand portable .
If you wanted a more hand portable version , I had an idea to put the battery pack in my back pack or make a belt clip and just run a rugged wire , maybe in one of those spring loaded spools that can extend in and out easily, then I could attach the light pod to a clip and clip it to my shoulder pad strap and have a shoulder mounted light thats easy to grab and point around , powered by a 10 or more AH pack secured in my pack as well as have a xt30 to quickly detach it . It could make a sick camping or hiking light ?!