That looks like what you find in a lot of public schools. At least from what I've seen.
Could be ok, but only ok. Could be garbage too. You'd have to try it out a little to see. Or have a piano tech look at it -- There might be problems such as not being able to hold a tuning.
Some people give pianos like that away for free. $15 isn't that much. It's going to cost several times that to get it tuned though. And you'd have to move it -- That's usually what people want who I see giving away pianos. They just want someone to move it.
If it's for a beginner and the piano is in decent shape, it might be ok. It's basically nothing for the price -- If they would deliver it for you, that would be a plus.
I didn't study the ad out much. I just saw a Wurlitzer piano there.
I wouldn't too sad if I didn't have that piano though either. A beginner could start out on one, but they could also start out on something better.