In Illinois a Firearm Owner Identification (FOID) card is required. There is a $10 fee to obtain this card. There is also a $2 fee for a mandatory background check.
430 ILCS 65
What is Permit to Purchase?
Some states require that a citizen acquires a permit, before they purchase a gun. If it is required, there will be a fee that varies from state to state. Some states also require finger printing, and background checks before issuing the permit.