For mustachian parents, cloth diapers are a good money saver. Just go workhorse (prefolds or flats and covers), not fancy (all-in-ones, pocket diapers) to maximize savings. Plus the less expensive options are way easier to wash.
I'll second the cloth diapers. I spent about 500$ total to diaper our child (including disposables while traveling and for a about a year when she was potty trained but not night trained). With some other mom friends we built up a huge semi-communal cloth diaper statsh that was mostly prefolds and covers with a few pockets. Since they were almost all still in decent condition after our kids were out of diapers, they have been recently passed on to a group of younger families in our area.
For my items:
- chest freezer and pantry space
- crockpot
- sewing machine (okay the hobby part is not very frugal but I do repair a lot of our clothing and make kid gifts from scraps)
- electric toothbrush (I have good teeth, but my spouse and child do not. The dentist has remarked that their teeth are showing less decay after switching. I'm aware that research shows that you can get similar results by properly using a manual tooth brush)
- Minera IUD (no menstrual products needed, no unplanned babies)
- sharp scissors for hair cutting (I cut my hair, formerly spent about 150$/year, and my daughter's hair, she's almost six and has never been to a barber/salon. My husband refuses to let me cut his hair, and won't learn how to do it himself.)
- cast iron pan (it's practically nonstick now - I can fry eggs, make pancakes, etc. It cost 20$ and will last until I can't use it anymore. It gets used almost daily. I even brought it on vacation!)