Your downpayment will be the same as with any purchase. Usually a 1% earnest deposit is given with the initial offer, followed up later with a 2nd deposit. How much money you put down can depend on the mortgage. You can have a mortgage but you should submit your pre-approval with the offer. Be prepared to wait a while for a bank to get back to you on a short sale offer. Some banks will answer fairly quickly; others may take weeks.