In your purchase agreement, the buyer either did or did not request a real estate appraisal. Any real estate buyer financing the purchase will be required to have an appraisal. This is a buyer expense that usually costs between $350-$450. In the event that the appraisal is returned at less than the agreed upon sale price, the buyer must alert the seller in writing. At this point the two parties may negotiate a new sale price, agree to keep the original sale price, or cancel the contract.