How quickly can I sell my car?

I have an '07 Mitsubishi Eclipse Spyder (Convertible) GT with 273 hp in great shape and no accident history. I've had it for about a year now it's got 16,000 miles on it, but I'm looking forward to sell it as a private owner (not to the dealership) I was wondering how long it might take for someone to make me an offer on ads and stuff. My offer is $16,000. Also, what is the best way to advertise it?