Pay-Per-Click Advertising: What Is PPC and How Does It Work?

PPC stands for pay-per-click. You only pay when someone clicks your ad. That's the entire pitch. Everything else, the auctions, the Quality Scores, the hundred different campaign types, is just the machinery Google and Meta use to decide whose ad shows and what it costs. Here's the honest, jargon-light version of how it actually works.

The basic transaction

You create an ad. You tell the platform who you want to show it to, and how much you're willing to pay when someone clicks. The platform runs a real-time auction every time someone searches (or scrolls). Winners show. You get charged only when the click happens, not when the ad's shown.

That "only when clicked" bit is why PPC feels safer than traditional advertising. You're not paying to be seen, you're paying for proven interest. Whether that interest turns into a customer is a separate problem, which is where most advertisers come unstuck.

The auction, demystified

When someone searches "plumber Newcastle", Google runs an auction among every advertiser bidding on that term. The winner isn't necessarily the highest bidder. It's the highest Ad Rank, which is roughly:

Ad Rank = Bid × Quality Score × Extensions × Context

Which means an advertiser bidding £2 with a Quality Score of 9 can beat one bidding £5 with a Quality Score of 3. Good ads cost less. Bad ads cost more. Google's business model rewards relevance, because relevant ads get clicked, and clicks are how Google makes money.

For more on this mechanic, Quality Score in Google Ads goes deeper.

The main types of PPC

PPC isn't one thing. It's a family of formats that behave differently.

• Search ads: text ads on Google when someone searches. Highest intent, usually highest cost per click.
• Shopping ads: product listings with images and prices. Essential for ecommerce.
• Display ads: banners on websites across Google's Display Network. Cheaper clicks, lower intent.
• YouTube ads: video ads before or during YouTube content.
• Performance Max: Google's AI-driven campaign type that runs across all placements.
• Social PPC: Meta, TikTok, LinkedIn, Pinterest. Different algorithms, different psychology.

Each suits different goals. Search wins for capturing existing intent. Social wins for generating new demand. Display wins for remarketing. Mixing them sensibly is the whole game.

How much does PPC cost?

Depends entirely on industry and competition. Cost per click ranges from 10p for niche queries to £50+ for insurance, law, and finance. The meaningful number isn't cost per click, it's cost per acquisition, what you pay to get a paying customer.

A £20 click that converts 10% of the time costs £200 per customer. A 50p click that converts 0.1% of the time costs £500 per customer. Cheap clicks are only cheap if they work.

Setting a sensible budget

Rule of thumb: you need enough budget to generate at least 30 clicks per day on your primary keywords, for long enough to gather meaningful data. For a £5 keyword, that's £150/day minimum, or about £4,500 a month. Spending less tends to leave campaigns underfed and inconclusive.

For very niche or local businesses, lower budgets can work. Nationally competitive categories need serious commitment or they're a waste.

What beginners get wrong

• No conversion tracking: judging success on clicks instead of customers. Fatal.
• Broad match everywhere: burns budget on irrelevant searches.
• One ad group for everything: terrible Quality Scores, expensive clicks.
• Homepage landing pages: generic page for specific query. Conversion rates tank.
• No negative keywords: paying for searches you didn't mean to target.
• Set and forget: PPC rewards active management, not autopilot.

What good PPC looks like

A proper PPC account has tight ad groups, specific landing pages, negative keywords curated weekly, conversion tracking through to revenue, and at least two ads being tested against each other in every group. The campaigns match the business, not a template.

The numbers aren't magic. Cost per acquisition trends down. Conversion rate trends up. Wasted spend shrinks. That's what you're paying for when you hire someone to run it.

Metrics that matter

Ignore the vanity ones. Focus on these:

• Conversion rate: clicks that become customers.
• Cost per acquisition: spend divided by conversions.
• Return on ad spend (ROAS): revenue divided by spend.
• Impression share: how often you show up in eligible auctions.
• Quality Score: the leading indicator of future cost.

For the full breakdown, Google Ads performance metrics covers every one.

PPC vs SEO: not an either-or

People often frame it as a choice. It isn't. PPC buys you instant visibility but costs per click. SEO takes months but compounds. Businesses using both, properly, outperform businesses using one. PPC tests demand quickly, SEO captures it durably. They feed each other.

When to hire someone

If you're spending under £1,000/month, run it yourself and learn. If you're spending £2,000-£5,000+, the opportunity cost of running it badly usually exceeds agency fees. If you're spending £10,000+/month without expert oversight, you're almost certainly burning money you don't need to.

Final word

PPC isn't magic and it isn't a scam. It's a marketplace. The advertisers who understand the mechanics, write decent ads, build proper landing pages, and track the right numbers, win. The ones who don't, subsidise the ones who do. Pick which group you want to be in, then behave accordingly.