There are print/copy shops everywhere, especially near universities - you should be able to type either of those terms into Google Maps for multiple options. There are at least 5 within say 10 mins walk of my apartment, for example (although I live near Gongguan, so that’s probably above average). I think the one I’ve been to before was like 1.2 or 1.5 TWD per A4 page.
What’s the difference between “per page” and “per side”?
A single-sided page at 7-11 costs 3 TWD.
A double-sided page at 7-11 costs 6 TWD.
A single-sided page at Carrefour costs 1 TWD (they couldn’t print double sided for me)
That’s surprising in this day and age; I bet they just didn’t know how to do it. I mean, I worked in a print shop back in the early 1980s and our Xerox machine could print double sided no problem.