While both cheap and very reasonably sized in the end... tbh I don't think I'd do this one personally. Assembling cubes smaller than a fingertip is substantially more difficult than something even slightly larger. The "fold each square in half" step does give you at least one sharp edge on every piece though, which helps a bit.

That gallery is great though, thanks for the link!

I have built an M1 sponge from business cards and I cannot fathom the thought of one person doing an M3 in miniature.