I have no idea if Naughty Baby nappies are available in the shops, my guess would be that they're probably not
I could be wrong tho! I know Mothercare sell Bambino Mio nappies and wraps and Waitrose sell the Close Parent PopIn snap-in nappies but as for the cheapies, I'm pretty sure there's no chance of getting them in the shops! If only, I'd have been down there buying loads
I usually get all my cheapies from an ebay seller called 97k Gallery. They're really good nappies for the money, I got a 9 pack for £31
I think he's got even cheaper ones now.
As for how many you'll need, it depends how often you want to be washing! A good amount to start with is around 20-25, so that you'll always have some in the wash, some clean ready for baby's bum, and some drying
Some nappies take longer than others to dry (microfibre is quicker at drying than bamboo or hemp)
I started out on full time fluff when I only had 12-15 nappies so I was washing every day, which wasnt ideal really. I have about 55 nappies now, and I wash every other day, just cos when my nappy bin is full, it's about a full load for the washing machine