Cold email vs Reddit vs ads: the real cost per customer
Worked arithmetic for a small SaaS, with every assumption stated so you can substitute your own. Includes what our own infrastructure costs to run.
Every channel comparison you have read was written by somebody selling one of the channels. This one is no exception, so here is the deal: we will state every assumption, show the arithmetic, and publish our own infrastructure costs. Substitute your numbers and the conclusion may well flip. That is fine. The model is the useful part.
The scenario
A B2B SaaS at €29 a month. Annual contract value €348, and with typical churn, lifetime value somewhere around €500. That is the number every channel has to fit inside.
The rule of thumb most people use is that acquisition should cost no more than a third of lifetime value, so the ceiling is roughly €165 per customer. Hold that number in your head.
Channel 1: Paid search
Assumptions, all adjustable:
| Step | Rate | Running cost |
|---|---|---|
| Cost per click, commercial B2B term | €6 | €6 per visitor |
| Landing page to trial | 3% | €200 per trial |
| Trial to paid | 20% | €1,000 per customer |
Against a €165 ceiling, that is not close. And the numbers above are kind: competitive B2B categories routinely clear €15 a click, which puts you at €2,500 per customer.
Paid search starts working when contract values reach four figures, or when you are bidding on very long-tail terms with little competition. For a €29 product on category keywords, the arithmetic simply does not close, and no amount of landing page optimisation fixes a 6x gap.
Channel 2: Cold email
The tooling genuinely is cheap. Domains, a handful of inboxes, a sending platform and a data source lands somewhere around €150 a month.
| Step | Rate | Monthly outcome |
|---|---|---|
| Emails sent | 5,000 | Across several warmed domains |
| Positive reply rate | 0.5% | 25 conversations |
| Conversation to customer | 20% | 5 customers |
| Tooling | €150 | €30 per customer in cash |
Thirty euros per customer looks like the winner, and this is exactly where most channel comparisons stop. Three things are missing.
The hours. List building, copy iteration, inbox warming, deliverability triage and replying is realistically twenty hours a month. At €50 an hour that is €1,000, taking the true cost to about €230 per customer. Above the ceiling.
The fragility. Deliverability degrades. Domains get burned, sending reputation collapses, and the channel has bad months for reasons you cannot see.
The compliance surface. Under GDPR, unsolicited B2B email to EU recipients needs a lawful basis and a genuine opt-out path. It is workable, it is not free, and pretending otherwise is how people end up with a problem that costs far more than any CAC number.
Channel 3: Reddit by hand
Fifteen minutes a day across six to eight communities, replying to people who are describing the problem you solve. Cash cost: zero.
| Step | Rate | Monthly outcome |
|---|---|---|
| Time | 7.5 hours | €375 at €50/hour |
| Threads worth answering | ~30 | About one a day |
| Reply to site visit | 2.5 visits each | 75 visits |
| Visit to signup | 30% | 22 signups |
| Signup to paid | 25% | 5 customers, €75 each |
The 30% visit-to-signup rate is the line people object to, and it is the one we are most confident about. It is not a landing page trick. The person clicking described this exact problem in public ten minutes ago, so they are not evaluating a category, they are checking whether the thing someone just described to them exists.
The catch is the ceiling. Roughly thirty qualified threads a month in a typical niche is not a number you can multiply. Doubling the time does not double the threads, because the threads are not there.
Channel 4: Reddit with the reading automated
Same channel, with the scanning removed. Reading every new post across eight communities is the bulk of the time and none of the value.
| Step | Rate | Monthly outcome |
|---|---|---|
| Software | €14 to €79 | Per product, per month |
| Time | 3 hours | €150, replying only |
| Threads surfaced | ~45 | Wider coverage, nothing missed on busy days |
| Customers | 7 | €23 each |
The gain is not magic, it is coverage and consistency. A person reading manually misses Thursday because something broke in production. The threads missed on Thursday are gone, and they were disproportionately the good ones, because nobody else answered them either.
Breaks down entirely below four-figure contract values.
€30 in cash, the rest in hours nobody counts.
Free in cash, capped by your attention.
Same channel, better coverage, fewer hours.
What our side costs to run
Since we are making a cost argument, here is ours. Reddit is read per subreddit rather than per customer, through Apify, which bills about $0.02 to start a run plus $0.004 per result.
Six subreddits at fifteen posts each is ninety results, so roughly $0.38 a day to read them. That figure does not change if one customer is watching those subreddits or forty, because it is the same read. Scoring adds one language model call per project per batch of posts.
This is why the entry plan is €14 rather than €99: the marginal cost of an additional customer watching an already-watched community is close to zero. We would rather have the volume. There is no trick in it and the pricing page is the whole story.
What this actually means for you
- Under €30 a month: paid search is arithmetically out. Reddit and content are the realistic options.
- €30 to €200 a month: Reddit for the first hundred customers, then layer content on top. Cold email if your market has clean, findable contact data.
- Above €500 a month: every channel opens up, and paid search starts making sense again.
- Any price, month one: start where the cash cost is zero. Reddit’s real advantage early is not the CAC, it is that you talk to people and find out why they do not buy.
That last point is the one we would defend hardest. The channel’s underrated output is not customers, it is the thirty conversations that tell you what is wrong with your positioning. No ad account has ever produced that.
If the arithmetic points you at Reddit, the practical version is in the lead generation guide, and the six-week starting plan is finding your first 100 users.