We have an 08 245rks which we purchased new for $20k, so $15k for an 06 is a bit high. I'm thinking new ones could be had for even less now.
Get the manual slide as others have suggested, when we check in at a campground I just pull the lever and place it in the extended position as a rule. No big deal, this way I can make any turn necessary to get in my spot without worrying about crushing my cab. Peace of mind is worth an extra few hundred bucks for a manual slider...
Sometimes I'll even extend the slider when I start looking for a gas station, they can be tricky sometimes, they look like an easy in out at first but when you commit you can get stuck.
Best of luck.
Ron W.