A publicity 'stunt' [stunt is not a dirty word!]Most businesses spend a lot of time and money devising great marketing activities based around a staple diet of SEO, Pay-per-click (Google Adwords, Remarketing, Facebook Ads, Twitter Ads, etc...), maybe some direct mail, email marketing, even radio if you have enough money. But these are all pretty much directly proportional in effectiveness to the amount of money you can throw at them.If you're wanting rapid, low-cost (or cost-effective) exposure, the best way to achieve that is to get everyone else talking about you for free. If you can devise something that's quirky, cute, different, or newsworthy, then you can rapidly get exposure to a massive audience for very little cost. This is what we call "earned media" as opposed to "paid advertising". If something you do, have, say can earn you some free 'airtime' (radio, TV, Twitter, Facebook, etc..) and it genuinely captures the interest of the masses, you'll achieve thousands of times more for very little cost than any form of paid promotion you can think of.If you can't think of something that's newsworthy and generates a lot of free exposure, the second best thing you may be able to do is form a partnership with another business/company/brand that also services the same target market. They are already working with your clients/customers, and if there's a reason for them to collaborate with you, they may help do the marketing of your product or service to their clients. An example may be a law firm that partners with an accounting or bookkeeping firm. Or a retail store that agrees to stock your products. Or a tradesman that strikes up a partnership with a real estate agency or property developer.BUT, if we really have to stick to the parameters of this question (Pay-per-click advertising), it's much harder to give a one-size-fits-all response. Perhaps the greatest value PPC advertising to actually multiply the effectiveness of any other paid advertising is Google Remarketing. Google Remarketing keeps reminding your audience of your brand for days, weeks, and months after they've visited your website. And you pay very little for it (in relative terms). One of the weaknesses of a lot of online advertising is that we frequently try to secure a client after a single 'impression' (view) of our advertising. But what if they're not ready to buy then? There's a good chance we've wasted our money, because we don't get another opportunity to remind them who we are and reinforce the message. With Google Remarketing, we can keep putting our message in them (embedded on hundreds of thousands of websites that are part of the Google Display Network) for months after they visit our site. This helps to reinforce our message and dramatically increase brand recall and goal conversion rates.