The second hand and refurbished market remains the best option, regardless of the form factor. You can get a more powerful, multicore, perfectly functionnal laptop, desktop or minipc with 4GB of memory or more for 100usd/€ while the pi price do not drop as much. In most case battery will be dead on the laptops but many people stick with old laptops with dead batteries for years and just use them as portable plugged desktop because they don't want to spend the money on a new computer.
Raspberry pi are really only interesting if you want to stick to the small form factor and the usually come without screens and keyboards.
EDIT: raised price from 50 to 100€ as a quick search only showed netbooks and laptop with 1 or 2GB of ram for 50€ in a 10km radius. In 2 minutes I found a Thinkpad T420 with crappy screen resolution 1366x768.
Yeah the pros of having access to a common architecture cannot be understated. You'd think ARM would be widely supported by now given that nearly every phone runs it, but every time one tries to do something vaguely nonstandard you run into walls that simply aren't there on x64 (especially with an AMD/Nvidia/Intel GPU and common net card instead of <insert SoC manufacturer's barely supported custom homebrew card>). There's a reason one cannot simply update Android phones to the latest OS without explicit vendor support and the reason why is not pretty.
Goes doubly so for the Pi specifically, since they stayed on 32 bit armhf OSes for the longest time which have even less package support and just straight up cannot run a wide range of software. And the new arm64 builds are laughably bad, having an almost 10-50% performance overhead on certain processes. And the Pi 4 is already painfully slow even compared to cheap android phones.
It is in most aspects an absolutely terrible way to get started with computers.
Conversely, for anything embedded or with hardware control aspect to it that needs more than an arduino or needs a GUI, Pi is the common architecture that has widely available hardware interfaces, code and community support available.
Yeah, if you're using it for web development or something it will suck to just try and install all the dependencies you need. But if you're making a 3D printer with a web interface, touch screen and maybe a camera, or a robotics project, it is by far the easiest thing to get started with.
Originally Pi was created to promote CS learning and I get that it has some shortcomings there but it sure as hell has enabled a lot of people to learn about embedded computing and robotics.
That's definitely true and why the Pi is so popular at all, but if you don't need to explicitly interact with hardware there are generally better options.
Cannot comment on that location but I've noticed a few sellers on ebay seem too just take older 4GB ram chromebook and install linux on them before selling them for $50-75. If you're not as lazy as I am you can do the installation yourself of course.
I think the raspberry pi is mainly interesting for its small size, GPIO pins and very low idle power.
And I have experienced enough times that actual durable storage medium would be a good thing. I think there should be better options if you just want small cheap box to run linux. Though the cheap is slight challenge.
Raspberry pi are really only interesting if you want to stick to the small form factor and the usually come without screens and keyboards.
EDIT: raised price from 50 to 100€ as a quick search only showed netbooks and laptop with 1 or 2GB of ram for 50€ in a 10km radius. In 2 minutes I found a Thinkpad T420 with crappy screen resolution 1366x768.