• An Aadhar UID is for  individual who is a resident in India including childrens,babies.
• person to be enrolled should be present at aadhar enrolment camp.
• NRI's need not to  apply for Aadhaar UID as Aadhaar is for indian residents only.
• aadhaar card is  free of cost .
• no money is required for any aadhar registration process including processing ,application/enrolment form

get more info here: who can get aadhar card ? cost?