Well, I guess their job with an ad is to catch your attention right? It obviously worked!
Whilst I don't necessarily like the approach myself, I don't inherently see anything wrong with it, because it is very clear that the scope isn't free.
If you had to click through to the site to find out if it's really free or not, then I think that would be dodgy, and I'd be asking them to remove it.
It's actually rather a clever ad.
Dave.