(a) Conveyances for recreational or historic-monument purposes to a State, county, or other State or Federal instrumentality or political subdivision shall be issued without monetary consideration.

(b) All other conveyances shall be made at prices established by the Secretary of the Interior through appraisal or otherwise, taking into consideration the purpose for which the land is to be used.

(c) Patents shall be issued only after payment of the full purchase price by a patent applicant.