How do I pick an inside lock?

I've locked myself out of my bedroom and cannot seem to find one of several keys. It's one of those very simple inside locks; every room in my place has the same lock. It's a gold door handle with a small hole in the middle, and the key, as I remember, is a small silver key, basically looks like a flathead screwdriver only thinner (with a small flat end). I'd hate to have to pay a locksmith, does anyone know how I could pick this with a bobby pin or something? I've tried at length to get it open with a flathead screwdriver, but it's not working... Thanks!