Reminds me of this one you’d get in magazines in the 90s. If I recall correctly it actually worked.

This was done back in 2014 with cell phones, glass beads and 3d printers and the cost was under a dollar:

https://ceramics.org/ceramic-tech-today/just-bead-it-glass-spheres-form-powerful-and-inexpensive-cell-phone-microscope-you-can-3d-print-at-home/

it was possible to print quality microscope lenses using a photopolymerizing clear resin on a Mars 3 Pro printer. In developing the specifications for their lenses, they followed those of the Edmund Optics 12.7 mm diameter plano-convex lens, which has a focal length of 35 mm

I didn’t open the paper to read more, but that’s the important bit if you’re curious like me.

The cost of high-resolution microscopes can be prohibitively high for millions of students and researchers around the world.

Now they’ll just need to spend $1,000 on a couple of 3D printers (FDM and resin) and supplies and bam you’ve got a fully functional microscope!

You can usually find pretty good used microscopes cheaply

One gets the impression the printer necessary for a lens eats the cost difference.