I shop at Aldi, farm co-op, and EVERYTHING is made from scratch.
I rotate my own curriculum and supplies. I have TONS, and when I find something inexpensive off season I can add it to my box then. Saves a bunch.
I no longer do paper anything. All notes to parents are online, menu, newsletter, everything. Ink was a HUGE expense.
I raised rates years ago and supply diapers and wipes. Amazon subscribe and save makes me come out WAY ahead.
I charge more per day for PT spaces than I do for FT. That pushes some 4 day kids to enroll 5 days, and those wanting set 3 days pay enough that if I don't fill the opposite two days, it's worth it.
No batteries.
No transportation. No field trips.
The dollar store is a killer for me, too. I only go there ONCE for party items and stick to my list.