Today I got a check for $318.74 from the state of New York.
After a certain period of inactivity, banks, brokerage house, insurance companies, and other organizations are required to turn over a customers' assets to the state for safe keeping. When you want it back, you contact the state it was turned over to.
I checked the database on the NY state website, and it reported I had unclaimed funds. I downloaded a form, filled it out, had it notarized and sent it in. About 6 weeks later I had my check.
I'm not exactly sure where the funds were from; I had done business with the institution in the past, though, and the state had the right address so I know it's mine. It was a pleasant surprise.
Check the websites for states you have lived in. You may find money you (or a deceased relative) did not know about.
Be careful, though. There are internet scammers that prey on the unclaimed funds issues. Some people will charge you a fee to do what you can do for free. Some may just be centers for identity theft, so exercise caution if you choose to deal with the 3rd parties.
The safest solution is probably to go directly to the states' websites. On the government site, search for "Unclaimed Property."
Here are the 4 sites I checked:
Let me know if you find anything. Good luck.