Seriously though, I would take her. Even if you aren't financially prepared to keep two horses long-term, why not get her, put a few months of training on her (assuming you have the means to do so yourself), then flip her if you can't afford to keep her? I don't know how good the market is in your area, your financial situation or your costs per horse, but I know around here you could turn a small profit doing that with her, provided you didn't keep her around too long and rack up the feed bills. Granted, it would be quite a small profit, but even if you only get 100 or 200$ for her...that's 100 or 200$ and several months of experience you didn't have before.
Though, delfina makes a good point. Why is she free? Even if I had too many horses and had to downsize, I wouldn't start handing them out for nothing unless something was wrong with them and I wanted them GONE. Reading the ad, people always tend to downplay a horse's problems. So 'insecure' and 'likes other horses' could mean 'dangerously herdbound'. I'd really take a good look at her and get her checked by a vet if you were to take her.
Were you wanting a long-term horse to keep with Lacey? Or just a youngster as a project horse to work on then sell?
"The problem with quotes on the internet is that many are not genuine." -Abraham Lincoln