I have only been kayaking for 3 years now, so take this with a grain of salt, but...
I will never own a kayak for my own use that is shorter than 13' again.
I'm not trying to say cheap rec boats don't have a place, they do, but if you have been renting a while and now want to buy your own, its time to step up to at least a day touring kayak. Consider what you have spent on rental fees over the past 10 years, and I bet you could afford a Necky Manitou 13, Perception Carolina 12 or 14, Current Designs Breeze or Kestrel 120, Old Town Dirigo 120 or 140, just to name a few. All of the above should track well, paddle easy, and allow you to go on longer voyages.
If money is a big concern, try craigslist. I have seen some 14' boats for $500 recently in my area, and Kayaking is really on the upswing around here. They might be older, but a good condition used boat would be better than a cheap new boat, IMO.