In reply to Kassius:
Only option I've done which was "free" - if you need a new card or an additional card anyway, buy one with a free (trial) recovery software. Last year I had a card that went faulty and just used the free recovery software (it happened to be unlimited in the number of files for recovery though I had to register to use it without limit) that came with a different sd card and it found and restored all the photos from the faulty card. Once these were on the pc I scrapped the faulty sd card.
If there are only a few files on the card, I believe some recovery software will give you a free trial without the cost of buying a new sd card.