Cost-per-lead is the number every vendor wants you to look at, because it makes their channel look cheap. Cost per saleis the one that decides whether you made money. Here's how to work it out honestly — and why most stores can't yet.
The short answer: the cheapest lead is often the most expensive car. Cost-per-lead tells you what you paid to make a phone ring; cost-per-sale tells you what you paid to put a deal in the finance office — and the two rankings are almost never the same. Once you divide spend by the units a channel actually sold(and look at the gross behind them), the "expensive" source that closes often beats the "cheap" one that doesn't. Most dealers can't run that number today, and this is why.
Every channel looks great on a cost-per-lead report. That's the whole problem — cost-per-lead rewards volume, and volume is the easiest thing in the world to buy. A source can flood you with cheap, tire-kicking, half-abandoned form fills and post a beautiful CPL while selling almost nothing.
The math that matters is one step further down:
If you budget off cost-per-lead, you will systematically defund your best channel and pour money into your worst one — and the report will thank you for it the whole way down.
Cost per sale is not complicated. It's:
Two words carry all the weight: by channel, and actually sold. Total marketing spend divided by total units is a fine board number, but it hides everything — it can't tell you where to move the next dollar. You need it split by source, and you need the denominator to be sold units that source can be honestly credited with, not leads, not "influenced," not clicks. Then you look at the gross behind those units, because cost per sale on its own is only half the picture.
Real, in-circulation benchmarks — useful as guardrails, not gospel. Your store's numbers depend on your market, your mix and your brand, so treat these as "is my number sane?" checks, not targets to hit.
| Benchmark | Rough figure | What it tells you |
|---|---|---|
| Common "healthy" target, total marketing per unit | $250–$350 / vehicle | The number a lot of dealers think they run at |
| Actual average ad spend per new vehicle sold | ~$739 / vehicle | The number a lot of dealers actually run at |
| Self-generated Google Search, cost per sale | ~$380–$765 / sale | Owned demand, on the cheaper end when it closes |
| Third-party marketplace leads, cost per sale | ~$8,000–$12,000 / sale | The eye-opener — and exactly why you measure per channel |
These figures are in-circulation industry benchmarks, not a single authoritative study — treat them as sanity checks against your own numbers, not targets.
That last row is not a typo, and it's not an argument to cancel the marketplaces. It's an argument to measurethem — some stores' third-party spend earns its keep on units they'd never have seen, and some is lighting money on fire, and a cost-per-lead report can't tell you which store you are. If sorting that out is your actual question, there's a full guide on measuring third-party ROI — this piece is the same math pointed at every line, not just that one.
Here's the trap laid out as a table, because it's the whole point of the guide:
| Channel A (cheap leads) | Channel B (pricey leads) | |
|---|---|---|
| Cost per lead | $50 | $100 |
| Close rate | 5% | 20% |
| Leads to make one sale | 20 | 5 |
| Cost per sale | $1,000 | $500 |
| Avg. gross per deal | $1,200 | $2,600 |
| Net contribution / deal | $200 | $2,100 |
Channel A wins the cost-per-lead beauty contest and loses on every metric that pays the bills. If your reporting stops at the first row, Channel A gets next quarter's budget. If it reaches the last row, you'd move every dollar you could into Channel B. Same spend, opposite decisions — and the difference is entirely in how far down the funnel you're willing to measure.
Most stores can't produce an honest cost-per-sale-by-channel number, and it's not a discipline problem. It's a plumbing problem. Three things have to sit in the same place, and in the average dealership they live in three systems that never talk:
To get cost per sale by channel, you have to join all three: this delivered unit → this lead → this source → this spend → this gross. Miss the join and you're back to dividing total spend by total units and calling it a strategy. This is exactly why the number is rare — and it's the same joined-up attribution the attribution guide is about. Cost per sale is what that attribution is for.
One more trap, because it's the one that survives even after you fix the plumbing. Two channels can post identical cost per sale — say $600 — and be nothing alike. One sells $2,800-gross deals; the other sells $900-gross deals with a chargeback waiting in three of them. Same cost per sale, wildly different businesses.
That's why the honest version of this metric always carries gross alongside it. Cost per sale tells you what the deal cost to acquire; gross tells you what the deal was worth. You need both in the same view, by channel, or you'll optimise toward cheap deals that don't make money — which is just the cost-per-lead mistake wearing a nicer suit.
Last point, and it's a hopeful one. Cost per sale has two levers, not one. You can cut spend — or you can raise the close rate on the spend you already have. Channel B in the table didn't win by being cheaper; it won by closing four times as often. A faster first response, a cleaner handoff, a lead that doesn't sit unanswered overnight — all of that lowers cost per sale without touching the ad budget, because the denominator (sold units) goes up while spend stays flat. The cheapest way to lower cost per sale is often to stop leaking the leads you already paid for.
You don't need a new agency. In order:
None of this is glamorous. But it's the difference between knowing what a car costs you to sell and guessing — and right now, for most stores, it's a guess dressed up as a report.
How do you calculate cost per sale at a dealership? Divide a channel's total ad spend by the number of vehicles that channel actually sold in the same period — not the leads, the units. $10,000 on a source that produced 10 delivered deals is a $1,000 cost per sale. Do it per channel, and look at the gross behind those deals, because two channels with the same cost per sale can make very different money. The hard part isn't the arithmetic — it's honestly crediting each sold unit to the source that earned it.
Why is cost per lead a misleading metric? Because it rewards volume, and cheap volume is the easiest thing to buy. A $50 lead that closes at 5% costs $1,000 per sale; a $100 lead that closes at 20% costs $500 — so the cheaper lead is twice as expensive per car. Budget off cost per lead and you'll defund your best-closing channel and overfund your worst.
How much should a dealership spend to sell a car? Benchmarks put a healthy target near $250–$350 in total marketing per unit, while the actual average runs closer to ~$739 — so many stores spend roughly double what they think. But the useful number is cost per sale by channel, not the store-wide average. Treat published figures as sanity checks, not targets.
Ad spend joined to the delivered unit and its real gross, split by source, so cost per sale is a number you can watch every morning instead of a spreadsheet you rebuild every quarter.