People currently in financial difficulty and need to pay debts off quickly will sometimes sell their properties at 70-75% of the current market value.
As a result, investing in below market value property has become quite popular in the UK and whilst some may find this practice unethical, a 'sell and rent back' scheme can allow families to stay in their home whilst reducing the level of their debt to a manageable level, or wiping it out altogether of course.
If you're an investor, buying properties at below the current market value with a large deposit, you can immediately build up a sizable amount of equity.
You may wish to purchase, refurbish it and sell it on for a profit or if the 'yield' justifies it, rent it out.