Eh depends on the place, I remember a clereance sale of GBA micros, they were selling them really cheap but I already had a GBA and two GBA SP plus the Micro sucks.
A brand new old 2DS Zelda edition is 50 bucks, so a used old 2DS should be going way lower that that.
Certain Chinese App...
Well 2DS were once sold at 80 bucks in the USA, and at once point were selling used quite cheap. A DSi in good state is a collector item but a regular old 2DS selling for more that 40 bucks is a scam. Just beware the DSi bricks more.
A DS or DS lite will never brick, a 2DS and 3DS bricking can happen but the DSi was made with a very brickable hardware unfortunately. It can even brick by just not being used for a while apparently?
https://gbatemp.net/search/7872002/?q=brick+dsi&c[title_only]=1&o=relevance
That sucks, a...
Use a 2DS/3DS (or DSi) instead of a DS or DS lite. Unfortunately most people has a 2DS as it was once only 80 bucks, and even less that that if you got this used, so there isn't many people using Twilight menu in plain old DS.
Don't get a DSi actually, not only they are ridiculously expensive...
Well not that many people has a DSi I guess? It works fine in my 2DS, 3DS and HD 2DS.
Literally you can find a used 2DS cheaper that a DSi so I guess is just a matter of lacking enough beta testing.
That explains why I already have it on my library.
It says something that a Nintendo 64 game in Japanese is best that this.
There is an English patch for the Nintendo 64 game, just saying.
Is a pain to use a different "tablet" unless you have a Japanese Wii U because Nintendo only sold spare tablets in Japan.
Now if you are asking how to hack the Wii U...
https://wiiu.hacks.guide/#/
That guide may be outdated, be warned.
The url on the flashcard itself or in the box the card came in.
That's usually the place were to get the firmware.
If the website is dead try the Internet archive.
Edit: Also this:
https://github.com/DS-Homebrew/flashcard-archive