If you want to save money, I'd recommend going a few different ways:-

1. Buy pockets. Most pockets are one size fits all - and some - like green kids - can be used for night and day use. Then you just buy more inserts than nappies because the nappy shell dries super quick - so you can use them pretty quick in rotation. So you don't need to buy as many "nappies" as such. Green kids are good for this reason. Itti bittis are good too (and you can get some as seconds so they are cheaper) but they are sized nappies.

2. Buy a one size fits all fitted - like a baby beehinds. These are great nappies - for day and night use. Then you just have to pay for the different sized covers that you will need.

3. Buy prefolds (because they are cheaper) and use them as some of your stash. Good for newborns - use flats at home - some prefolds - and use the proper MCN when you go out. Cheaper that way.

It is expensive - but its cheaper than paying $20 a week for something you just throw in the bin
At least if you buy one size fits all ones - you can get 2 years out of the one nappy.

ETA - and look on sites like buy for baby - they have people selling second hand nappies and you can pick up some really really cheap.