Best place to find cheap, used like new kayaks?

I have been longing to have a couple sit-on-top kayaks for years. I love kayaking! Being out on the water is revitalizing, and it's great exercise too! However, I don't own my own kayak, and I'd be able to go more often if I did. I don't want to spend upwards of $700 to get one, does anyone know of a place I could find one for less money? Trolling craigslist or let go unfruitfully for weeks looking for one gets old quick.