I recently had a flash drive that literally made a "crack" type of noise and all my stuff was gone.
Being loathe to lose the photos on it and pay for a commercial package to get them back, I came across a free open source utility called PhotoRec :-
TestDisk Download - CGSecurity
You have to run it from the OS X terminal but it did "exactly what it says on the tin" so it may come in useful for people in the future because flash drives or usb sticks are not 100 percent dependable. There is also a PC version which one runs from the command line (DOS prompt).
It is a bit "geeky" but is straightforward to use, mostly selecting options with the arrow keys and then pressing the return key. Despite its name, it attempts to recover all types of files.