Can I get a mortgage with bad credit?

Last time I checked my score was a 620. I have enough to put half the purchase price for down payment on a house is it possible to get a loan for the other half I do not care what the interest rate would be because I make enough money to pay above what the monthly payment would be to pay the loan off faster and I only want the loan for 15 yrs. Either way the payments would be cheaper than rent at this point. My credit has charge offs and write offs due to a lay off 8 yrs ago which caused me to lose everything. Paying back the debt is not an option because I consulted with an attorney about filling bankruptcy which I was unable to do because I had to much in liquid assests and he told me not to file,and not try and repay the debt (1) because I would go broke trying and that is stupid,and (2) because they have already been written off which means they have filed it as a loss on taxes so it would be double dipping . The main thing that shows up on my credit is a repo from 8 yrs ago it was auctioned off and they have never contacted me nor came after me regarding any excess amount owed but it still shows up on the credit report as well as all the other crap I lost. I was under the impression that after 7-10 yrs all the stuff is supposed to come off your credit anyways,so why is it still showing everything from the beginning of my credit history to now? some of the stuff is 10 yrs and older(older being the good payment history) I even got a credit card to start a payment history a yr ago and that was how I got my credit score up to the 600's it was worse. I just want to purchase a home I don't want to be stupid and buy up a bunch of other stuff on credit I just want to get a house , and pay cash for everything else that way if something were to ever happen again and I lose another job I will never be back in the position I was in before. Is it possible to get a loan with my credit history if I pay for half the value of the house up front?