It shall be the policy of the State of Illinois to acquire a system of State parks which shall embody the following purposes and objectives:
The Department of Natural Resources is authorized on behalf of the State of Illinois to accept by donation or bequest, to purchase or acquire by condemnation proceedings in the manner provided for the exercise of the power of eminent domain under the Eminent Domain Act, or by contract for deed payable over a period of time not to exceed 10 years, or in any other legal manner, the title to all such lands, waters or regions, and the easements appurtenant or contributory thereto, which shall be in accord with such policy in respect to a system of State parks, for the purpose of which the General Assembly may make an appropriation. Purchases by contract for deed under this Section shall not exceed $20,000,000 in total purchase price for land under contract at any one given time.
20 ILCS 835/2