The term broadcast advertising applies to commercials aired on either television or radio, which are typical called spots. It's also known as on-air advertising, and it's the primary revenue generator for commercial television and radio stations. This is all considered to be above-the-line advertising.
Broadcast Advertising Costs
As an advertiser, you will pay for a spot based on multiple considerations, including length, the time the spot goes out, which channel it is on, and most importantly, which show is airing at that time.
This purchase will be handled by the media department of an advertising agency, or a media buying agency, whose job is to negotiate the best rates and times for the commercials. Spots can vary in length, some being just 5-10 seconds, others going as long as the whole commercial break. However, most spots are either 30 or 60 seconds on television, and 15, 30 or 60 seconds on radio.
A spot airing in the commercial break of a prime time show will be very expensive, whereas spots that air on lesser watched channels after 12am will be much more affordable, with the price of $5 per 1000 viewers being typical. But, you will get fewer eyeballs on your ad. If you want a massive audience, a Super Bowl spot is the way to go, but the cost of just 30 seconds is going to run around $1-$2 million!
Creating Spots For Broadcast Advertising
Of course, before you buy air, you also have to produce the commercial, too. It's estimated that the average cost of producing a 30-second spot is around $350,000, and that's not including the cost of buying the airtime. But if you're smart, and have a great idea that doesn't require a huge budget, you could produce a spot for as little as $1000. That would mean excluding any advertising agency and doing it yourself, which is never advisable.
Another form of broadcast advertising that proves very popular for generating sales is direct response television (DRTV). This is advertising that asks for the sale, and gives you a way to order direct via information given in the ad. This is not concept-driven advertising, and usually follows the formula of demonstrations and a repetition of benefits.
The late Billy Mays was a master of this craft, generating thousands of dollars per second during a popular spot. There are usually two forms of DRTV, the short form commercial which lasts 1-2 minutes, and the long form version which will last around 30 minutes and often have a live audience, multiple demonstrations and many chances to call and order. The most popular name for this type of advertising is the infomercial.
If you've ever heard the phrase "but wait, there's more" you'll be familiar with the way the infomercial works, when offers are rapidly discounted to encourage people to pick up the phone and call. Ron Popeil, creator of the Showtime Rotisserie, is a legend in this form of advertising. However, it is frowned upon by most large advertising agencies as being a cheap, down and dirty way to get sales, and is not considered a good way to build a quality brand (would you buy Nike shoes from an infomercial?)
Before the Internet, broadcast advertising was the most popular way to reach a mass-market audience. These days, with the Internet being so widespread, and digital video recorders (DVR) editing out ads, broadcast advertising is not the sacred cow that it used to be.