Free isn't free in that it takes more time and effort to accomplish what you would easily accomplish if it was paid for. Also, take time polishing up your pitch if you are going to cold call, distressed situations are very distressful for the seller, they are wary of people trying to take advantage of their situation- why should they talk to a total stranger? prepare yourself for wow factor. And finally, you will need money to make money, if you do find a deal, you have to think of an Earnest Money Deposit and such like expenses...are you sure you want to do this right now?
having said that, here are some ideas:
1) Walk/Drive around your neighborhood look for signs of distress like unkempt homes.
2) Talk to your postman, ask him if he knows of any vacant homes.
3) Go to the local courthouse for probate leads or find them online on mypublicnotices.com if your state lists them there. Also the local classifieds attimes have the probate names.