I used a program call Recover my Files. I had reformated my harddrive after copying ther things I wanted to keep, to and external harddrive. Yep you guessed it..........the external drive died when I tried to reinstall. I bought this program for 69 dollars after trying Recova and many other ones. I knew what file names I wanted and Recover my Filles got my 15 years of Quicken check book files back. For shits and giggles I've tried it on all my thumb drives and some other harddrives. Tons of files left. If all you did was delete your sd card it should be pretty easy to get it back, as long as you dont go writing stuff back on it. Recover it form another driver to another drive and then copy back.
FWIW I will never sell one of my harddrives or thumbdrives. Those are reserves for a 10lb sludge hammer. Small price, considering the price of a new hard drive. The amount of personell info flying around on ebay is phenomenal and very easy to recover, since most people dont have a clue.