As shel stated there is no connection between 457 and PR.
Skills Assesment : xyz (ACS for IT is 400 AUD)
IELTS : 330 AUD per person in Australia. Better do it in india. chances are higher and cost is low
Application form : 2960 AUD
PCC (Indian) : 48 AUD per person. Can do from india as well
Police clearence (AUS - if you have stayed in AUS) - 45 AUD per person
Medicals (If done in AUS) : 317 AUD per person
thatz all.