Choosing wipeable covers is another affordable stash-building option without compromising on performance.
The wrap/cover will dry extremely quickly after washing. So you will need far fewer than you do inserts. Plus as long as the wrap/cover isn’t soiled, you can simply wipe it down at change times and reuse (around 4 times).
As the outer part is the most expensive it means you can cut costs right down. Around 4-5 wraps/covers would be sufficient for full-time usage.
Ai2s have their own inserts, which normally popper into the cover. These are a slightly more expensive option. They’re handy to have, but not essential. Often brands use the same sized popper (normally a single popper), so whilst not guaranteed, there’s a chance you could pick up some cheaper inserts for your chosen cover.
But whether you choose an Ai2 or wrap, you can use whatever inserts you like. This could be inserts you already own. Prefolds or flats in a padfold. Or anything absorbent, think outside the box, flannels, cut up tea towels, or even old t-shirts can all offer excellent absorbency.