I like to reuse paper that's only been printed on on 1 side for small documents that I'll print, read and then discard. Unfortunately my Brother MFCJ430 printer sucks at drawing in multiple sheets of used paper (new paper works fine). To avoid ink smearing and paper jams, I usually load 1 page at a time into the feeder, print 1 page, load another sheet, print another, etc.
It seems that the printer performs a mini cleaning cycle after each print job. Assuming this cleaning consumes some ink: Am I wasting lots of ink by printing 1 page at a time? Or is the ink lost negligible?
I found this blog article that did tests (50 pages) for various printers. Printing in a batch does indeed consume more ink but the test setup used had long breaks between individual prints, including a variant where the printer would be switched off in between. The results vary considerably though with printer models and electricity costs should also be considered for the overall cost.