Is it permissible to participate in a public auction for a property offered for sale by court order due to non-payment, given a condition that grants the original owner the right to reclaim the property within six months from the date of the award, even if the final awarded value is less than the property's estimated value by the expert?

It is permissible to sell the debtor's property to settle his debts, provided it is sold at market price. There is no harm in a slight, commonly accepted reduction. If the expert's appraisal represents the market price, the judge is not permitted to sell the property at a price significantly lower than this appraisal. If you wish to purchase, you must pay an amount that completes the price to the market value; otherwise, it is not permissible for you to buy at that time, because compelling an insolvent person to sell at a reduced price is coercion without right. There is no objection to granting the property owner a six-month grace period to revoke the sale, as this falls under the permissible option of stipulating a condition (khiyar al-shart (definition) al-mashru').