The purchase of supplies and equipment and the procurement of services for all branches under the Architect of the Capitol may be made in the open market according to common business practice, without compliance with section 6101 of this title, when the aggregate amount of the purchase or the service does not exceed $25,000 in any instance.

Lumber and other forest products produced by Indian enterprises from forests on Indian reservations may be sold under regulations the Secretary of the Interior prescribes, without compliance with section 6101 of this title.

The Director of the Congressional Budget Office may enter into agreements or contracts without regard to section 6101 of this title.