I'm not sure what a print plate is. A printed circuit board?
Maybe a Pi shop will assemble it for you, but I think it's safer to ship out of a case.
The pi4 snaps into its plastic case. It takes a minute or so. No tools are required, just enough light to see which way the Pi lines up with the corresponding cutouts in the case. The top of the case then snaps on.
Technically, I suppose, it's not a "finished" product, but once it's in its case, a trivial task, it's as finished as any other device. I wouldn't spend $500 just to avoid this bit of very trivial assembly.
One more simple task: write the operating system image to the micro SD card. I would download Etcher (free) for this.
After that, configuration is also similar to many other consumer network device I've used: connect the Pi to the router, navigate to its IP in a browser, set your wireless info.
https://www.pishop.us/product/raspberry-pi-4b-starter-kit/