In terms of economy, I use fluffies nappies that I've picked up in opshops while we are at home. I find myself changing bub every 1/2 hour to hour. If he is in a good fitted (bubba J hemp, BBH or BBB etc) I usually get away with changing every 2 to 3 hours (barring poos, etc). Say a fluffie costs $11 new, and a fitted $25 new, you can say that you would only need half as many fitteds

. Fluffies come in two sizes, up to 6kg and 5 - 11kg. The BB and many other brands are one size which covers this range plus more. If you're paying 50c for them in an opshop, fluffies are worth having to pad out your stash, but buying them new is false economy
For a newborn, nothing can go past a pack of flannelette flats in terms of ease of use, affordability and quick drying time. They are always in use here, and I have a huge assortment of Modern Cloth to choose from :lol