I bolded the part in the description that doesn't make any sense to me. Why would she put this in the ad, and then "be honest" and tell you she has sidebone when you contact her? That will be a HUGE maintenance issue. Why would she said "no maintenance"? It's contradictory.
Can the seller provide you with a video before you go look at her? Because, if she's dead lame in a video, then that might change your mind about considering her.
I'm not afraid of selecting a GOOD-minded horse that has some issues. However, you also don't want to be fighting an uphill battle if the horse is extremely lame.
As others have said, if you even do consider her, a full PPE is in order.