Best budget compact Non-Rechargeable Battery Torch

The Maglite Solitaire LED is a nice little single AAA that is very simple and easy to use. I would store it with a Energizer Ultimate Lithium since these won't leak and have a 20 year self life along with being able to work in cold temperatures. Alkaline and NiMH batteries also work very well in this light. The Streamlight Microstream is another single AAA option, this one has a clicky tail cap, while the Solitaire is a twisty.

The Lumintop Tools would be a good fit. Both the AAA and AA (Version 2.0) are tail switch with a nice clip, and have three light levels.

My son is a scout, so I found myself asking this very question at one point. We obviously have several we use on different outings but as far as a "one size fits all" type light, here's a few considerations around your price point....

Wowtac A1 is under $20 and includes a USB chargeable 18650 and puts out a respectable 550 lumens. The more powerful A1S model is over 1000 lumens but around $25 or perhaps a bit more. Includes a battery as well.

For something a bit smaller the single AA powered Fenix E12 has been with me for countless scout trips and seen a fair share of abuse and just keeps working. Nice robust little light.

If you need something smaller, I believe the AAA Tool might be a tad shorter? Best of luck.

How about:

Olight I3E EOS ($9.99 MSRP, 1xAAA). It's single mode. 70min runtime at 90 lumens. Waterproof to IPX8. Attaches to a keychain via a tiny split-ring.

It's not very large, but it works.

There is one downside to these. If you have an alkaline battery inside for a long time and it leaks, it WILL destroy the flashlight. But this is true of just about any aluminum flashlight with Type II anodizing--the alkaline battery will eat through the metal.

Keep the AAA battery separate from the flashlight while both are stored inside the first aid kit. But some of your scouts will be forgetful and leave batteries inside their lights for ages. Luckily, these are so inexpensive you can bring spare flashlights.

If you want brighter, you'll probably have to sacrifice on runtime or switch to not-so-common batteries like CR123A or the various high-power rechargeables.