I tested buying some of the expensive links on sites like forbes a few months ago, spent $4k on 5 posts. I was primarily getting them to see how the traffic converts but still underwhelmed by the ranking increase. I understand there isn't enough authority on the page but they literally only took a medium-hard keyword from page 8 to page 6 and even that may not be solely down to them, they got a decent amount of fb shares etc aswell. Now they aren't passing that much traffic and I'm not that bothered if 1 or 2 get deleted I can't decide if its worth sending decent pbn links at them or not. With there being so many internal and some outbound links on the page I'd lose loads of the 'juice' right?