If you're offering me money to link you, then presumably you believe your content is not of high enough quality for me to link you otherwise.
You seem to have misunderstood the difference between an advertising agency and a SEO company. What you're describing is what advertising agencies do, SEO companies are spammers that sell access to their spamming tools. It's similar to the difference between an agency practicing law and having them send a cease-and-desist, and buying a DDoS.
Not that I'm particularly fond of any of that, though I have lawyers practicing in another area as customers.
Some of you guys need to get your heads out of your butts and realize how the real world works. It's not just black and white all the time.
Email spam is cheaper than news paper adverts, does that make it "legitimate"? Because that seems to be your argument here.
Sorry, but I'm not willing to have this discussion. As I said, you'd better grow up and face the realities of the world you live in.
At this point, the argument has lost good faith.
ADDENDUM: for comprehension, not plastic surgeons.