That sounds like a decent deal for a 7-in-1 convertible, since those usually retail for quite a bit more new. The rocking feature is handy in the early months, though once baby gets more mobile you might not use it as much. If the condition is good and all the parts are intact, $200 seems reasonable for a lightly used one. Worth asking the seller for photos of the mattress and hardware just to be sure everything is complete.