[DrTiTus]

Assuming all figures are just guesses:

50 thimbles from a 1kg roll (@ 20g including supports and base layer)
$25 for a 1kg roll of ABS
15-20 minutes printing per thimble
Call it 2 days work (16 hours) to print 50 of them with loading, removing, delay between jobs because you got bored, etc.
Materials alone might be 50c, without power + printer costs.

If you can sell them for $1 each, you've "doubled your money" in two days (woo hoo!), but you've made $25 in total for 16 hours work (oh what?). Then consider tax + expenses, and you're effectively running a charity. That's where scale of injection moulding comes in, because you can't make it print any faster. Clothes pegs are manufactured and sold for a profit, and they're sold cheaper than medical items, so there has to be a way to do it - no normal person is 3D printing their own clothes pegs, for good reason.