I'm just getting started with playing piano, after playing guitar and studying music for the past 5 years or so.

Anyway, I was looking at the Casio Priva PX-100, since it's amoung the few digital pianos I can actually afford...but I was wondering about pedals. It seems that all the digital pianos with pedals are in the 1000 dolar range..i really want 88 keys and pedals would be nice to...could you buy pedals separately? Does it come with some digital feature that is comparable? Or are pedals really necessary? Thanks for any help

a sustain pedal is absolutely necessary if you want to get into piano. you should check the rear or side of the casio and see if there is a plug for "sustain". if so, you can buy most any $20 pedal from the music store and plug it in.

ideally, a good digital piano should have another jack for "soft" and the higher end models will have a third one for "sustenato".

You can, but the pictures like at
http://www.musiciansbuy.com/mb/item.asp?ic=PX100KIT2
or
http://www.kraftmusic.com/catalog/keyboards/88keykeyboards/2884

show it with a sustain foot pedal switch.

The specs on the Casio site are rather vague, but suggests it has three pedal jacks, but I'd guess only the one pedal switch, because that is all the online ads show.