I went stright for the 6 pack of bitti dlish (snap in one) when I bought mine and they worked great for me so I was lucky!

I agree with Pheonix though buy a trial pack to see what works for you, it you go into Itti Bittis website go into 'Trial and Bulk Packs' down the bottom they have a Bitti Dl'ish Trial Pack for $49.95, I also suggest to go into Accessories and buy a 'Bitti D'Lish Bamboo Snap on Mini Booster' for $3.50, just buy one to try with the snap in nappy that comes in the trial pack, that way you can see the benefit of the bamboo booster, I use these with all of DD's nappies, gives her an extra hour in her nappy, she can last 4 hours if needed.