Any body corporate holding land may sell, exchange, or lease the land for the purpose of the erection of houses for the working classes at such price, or for such consideration, or for such rent, as having regard to the said purpose and to all the circumstances of the case is the best that can reasonably be obtained, notwithstanding that a higher price, consideration, or rent might have been obtained if the land were sold, exchanged, or leased for another purpose.