Last year the FDIC published some useful tips on bank safe deposit boxes including the reminder that FDIC insurance covers only deposit accounts, and not the contents of safe deposit boxes.
A recent article on safe deposit boxes mentioned the typical rental costs of safe deposit boxes to be from $100 to $300. From my experiences you should be able to get a small safe deposit box for much less than this. And don't forget that many credit unions offer safe deposit box rentals. I only pay $12.50/year for a small box at my local credit union.
Another way you can get a deal on a safe deposit box is if you have a premium checking account at a bank. A premium type of checking account can often be free of monthly fees if you have a high enough balance in a CD. A free safe deposit box is a common perk with these checking accounts. However, it's typically only free for a small box. So if you need more space or if the bank doesn't have any more small boxes left, you may still have to pay.
When I opened a 5% 3-year Wachovia CD back in 2008, the banker upgraded my checking account to the premium checking version which qualified me for a free safe deposit box. Since my credit union safe deposit box had a low cost and was more convenient for me, I passed on the deal.
One useful tip mentioned by the FDIC is to use zip-lock bags for contents in a safe deposit box. If flooding occurs, your contents won't get water damaged.
In addition to storing important documents, I also store a backup of my hard drive in the safe deposit box. I don't have many pictures or videos so I'm able to store all my electronic documents on a USB flash drive. Each year, I'll replace the old flash drive with a new flash drive of the latest contents of my hard drive.
Do you have any tips about saving money on safe deposit boxes or what to keep in them?