Congrats Mum-to-be!
I am not a fan of one-size nappies. My personal opinion being that they tend to not fit well at the smaller & larger ends of the scale (e.g. gapey legs that don't seal well on a small baby, and builder's crack with too short a rise on a toddler). My preference is for "sized" nappies, they usually fit better for that particular stage, though of course most babies will need at least 2 different sizes from birth to toilet training. (and also there can be quite significant differences in fit between brands).
I started sewing for my kids really early on, so the cost of having sized nappies was pretty insignificant (I could make a pocket nappy for about $6 each - since labour was free of course

). Only basic skills are needed if you think you may want to give it a go!
If you do decide to invest in ready-made sized nappies, keep in mind that although it appears to be a costly "up front" way to go, it will still be cheaper than using sposies. And I hold onto the belief that the more nappies one has in their stash, the better condition they will be in for the next baby or on-selling, so be kind to yourself and have a good stash to help with the washing stress side of things (wet days, sickness, etc).
And my advice as always, avoid buying a lot of one type of nappy until you've given it a good test that it fits your baby well & that it works for your family (e.g. check that Grandmother can actually use snaps and DP/DH can stuff the pockets). Some recommend using sposies on a newborn baby, but I used cloth from birth for my boys (discovered cloth when #1 was 3 months old, so have bad memories of inferior sposies for her

With her pooing up her back all the time, cloth nappies would have been
less washing.)
So, my personal recommendation;
Hire a newborn/small kit (this should give you a taste of the different systems; AIOs, pockets, fitteds & covers, prefolds & covers, etc), or watch the trading post on here for cheap preloved nappies, or use sposies for the first weeks until you get your ahead around the sleep deprivation, cracked nipples, and finding a rhythm with your new stage of your journey.
Once baby has chubbied up a bit (or not, my boys were never chubby) and you've been able to test various brands/styles, you may wish to invest in a set of one brand, or continue with having a mix of nappies. Just keep in mind that your baby's shape is likely to change a number of times over their nappying days. It's not a problem when they're sposies and you can use up a packet then buy differently, but you don't want that happening if you've both 2 dozen pockets that are supposed to last to toilet training.
Sorry for the waffle, hope it helps
