Dr. Lee, Here is one possible version of a banner ad for injectibles. On the final panel you could offer $100 off and when they click they go to a landing page with a coupon for $100 off of any service of $300 or more.
I usually create one horizontal ad, one vertical ad, and one that is almost square. Then I run them on the Google Display Network.
They do NOT appear on media sites (they sell their own inventory). They do appear on all kinds of websites and on
YouTube pages.
These banner ads cost much less than Adwords (paragraph ads). They usually are 1/4th to 1/8th the cost of those paragraph style ads.