How can I fix a card read error when it turns on?

My camera was working normally after the first few months of buying it off of Ebay. Now, most of the time, when I turn on my camera, it pauses, the green light flashes three times and a big white box that says, "Card error. Reinsert the memory card then turn off and try again." I have tried 5 different microSD cards; new, old, less memory, more memory, different brand. Nothing has changed. Is there something I can do to fix it? Is it totally ruined and nothing can be done? Are there repair shops that can fix it? Please let me know.