1) By in bulk during sales and save receipts so that you can change the size if the need arises.
2)Don’t be afraid of to try a new brand. I live in Israel. Many Americans here buy either Pampers or Huggies. I decided to try Titulim Premium which is an Israeli brand. I find that they are great, significantly cheaper, and there are usually sales on them in big chain stores.
Same goes for wipes. I think I have tried every brand. I am not afraid to try new brands and I usually try the ones on sale. I never came across a BAD pack wipes. SOme are not as moist and others dont dispense as easily, but I found that I don’t need to buy the Huggies brand which is the most expensive.