Renderer Pixelation

I want to make an old-school looking game. Whatever the camera is rendering needs to be brought down to an extremely small resolution to get a similar look to old DOS-based 3D games, stuff like that. Sort of like the pixelated effect from this package, but I don’t really want to spend $100 just for one image effect. Any idea where I could find an effect like this on it’s own, or how I could go about making one on my own? Or are there any tricks I could use to just render at a low resolution?

Edit: My first thought was to use a RenderTexture, but I need pro for that, which I don’t have

Offhand, I would think you might render to a low-res RenderTexture, then stretch that RT to full screen.

I’m thinking with Unity Free is should be possible to do this with a viewport, set the viewport to a very small segment of your screen (320x200 for example), then use something like described here to copy the screen into a texture:

But modify it to only copy the 320x200 viewport we drew into, then draw that full screen.