Mish, it is expensive as you have to buy them now rather than over the course of 2-3+ years. However, on a preg mag I saw last week there was an offer for a year's worth of Huggies (note ONE YEAR, not ALL NAPPIES) valued at £1,000!!! It really adds up, one pack of sposies a week or whatever.
Over the course of your nappying you save a fortune - and they're free other than washing for other babies!
I wouldn't recommend a birth to potty nappy at this stage as they're not known for fitting well through to toddlerhood, and really they're therefore only worth it if you also get the smaller end of use. That said, they're very good!! And you can use them on your next...
I would go for 2-size nappies, eg Tots Bots, Bambineo, or many others, and get the size 2 nappies, which will take you through.
Songbird - yes they will work fine.
Emma