You should consult with your real estate professional, depending on the way that your purchase contract was written, there are a couple of clauses designed to protect you in this situation.
The first, your inspection period, allows for you to inspect the property during the first part of the escrow (usually defaults to 10 days from contract acceptance on an Arizona purchase contract unless a different timeframe was selected). Before the end of your inspection period, you have the opportunity to cancel the contract and have your earnest money returned to you if there are any major flaws with the property on the Buyer's Inspection Notice. If there are repairs necessary and you wish to move forward, this is your opportunity to ask for them too.
The second is the clause written into the contract concerning the appraisal. If you are obtaining financing, the lender is going to require the property to be appraised at least at the value that you agreed to purchase it for. If the appraisal comes in low, the seller will either need to drop the price, or you will need to make up the balance with cash to appease the lender you are getting your mortgage from if you want to keep the contract going. Otherwise, the appraisal coming in low is grounds for contract cancellation.
You definitely need to talk with the real estate agent who wrote your offer, they should help you through all of this. - Sat Dec 25, 2010