There’s a reason advertising rates are radically different for different media partners. The short answer is: “Not all media are equal.” The longer answer lies in the term: Measured Media.

Measured media, by definition, is exactly what it says. But measurements vary widely. The first rule in paying for media is to make sure it’s measured. The second rule is to determine if the measurement is credible — done by a third party resource, or auditor. Media that is audited can prove through outside resources the claims they make on reach and demographics. Then, since you know what you’re paying for, the cost to affiliate with these legitimate outlets is also usually higher, but definitely more valuable.

It is true that there is no such thing as a free lunch and also true that cheap lunches can get you food poisoning. The same is true in advertising. Free media means it has no value. If someone is giving you a spot for free, you know they couldn’t sell the spot. If they could have, they would have. This is particularly true in broadcast with a set 24-hour cycle and a set amount of spots to offer.  Morning drive programs in radio, for instance, are very popular and filled with paid spots because of their proven reach. Discounted or free ads, as a result, rarely if ever run during morning drive time. Free spots are commonly run in the wee morning hours and on weekends when paying customers won’t pay for the radically reduced reach, listenership, or viewers.

With measured media, measurements vary by type of media. Outdoor billlboards use traffic numbers called DECs, or daily effective circulation, provided by the Traffic Audit Bureau. The numbers tell you how many cars are likely to pass a billboard, but not how many people actually see the ad. The measurements are credible and allow a buyer to value one billboard over another. News in print is measured by Scarborough, broadcast stations are measured by Nielson or Arbitron, and online sites are generally  measured either by  Comscore , Alexa or Google Analytics. These third party research agencies are reliable and stake their reputations on being unbiased, although they can’t always be used to measure one type of media against another.

Social media historically had no measurements except followers or likes, which did not measure anything but one-time popularity. As it gets more sophisticated, especially in terms of taking advertiser dollars, the Facebooks of the world are providing metrics, but unlike with other measured media, their measurements are their own. By definition, it makes the numbers worthy of some skepticism.

So if you’re considering a discount coupon on the back of a grocery receipt or a Facebook ad, know that you are getting what you pay for. In the first instance, you have no idea how many people actually see or care about your ad. You only know how many times it was printed out by the register. With Facebook, you get more refined demographic reach, but again have to rely on Facebook’s word, not a third-party provider, that you received the impressions you wanted. Neither are measured media, just media with a measurement. There’s a huge difference.

The Walk-Away:  In advertising as in everything else in life, you get what you pay for. It ‘s the reason a Superbowl ad costs millions, Facebook ads are close to free and there are all levels of media costs in between. Make sure you’re buying media by what you need and not just by what it costs, or you could end up with a bargain that’s really no bargain at all.