At first, of course it seems really high, but honestly it depends on how much money you make from your website. If I had a million dollars to spend, I wouldn't think $700 was too much for an extremely high quality legit looking link from a high authority site. What do you think if the link only gives you a few hundred new visitors in the month and nothing more? Will you cry about wasted money, or just be happy to bump your domain authority a little bit? If $700 isn't too much to YOU, then sure just go for it. If it's too much for you, then don't.