What size tank? Are you planning on a community tank? Generally, Flowerhorns are best kept alone in at least a 75. Some people are successful with keeping them in communities.
I know of a local Red Dragon for $120 as well. If it is the same one that you are talking about, I think it is a good price.
Flowerhorns are a great choice. Very aggressive and interactive with their owners and fun to watch grow.