Build This Product: A Budget Planner

Take one product from idea to first sale: what to build, who buys it, what to charge, and how to deliver it without building a store.

27 September 20269 min read

Most digital products fail before anyone sees them, because the person making them started with a format instead of a person. "I'll make an ebook" is not a product idea. "I'll make the thing that stops a freelancer guessing what to charge" is.

So this series works the other way round. Each article takes one product, says who buys it and why, and walks through building it — including the parts that are boring and the parts that decide whether it sells.

First up: a budget planner. It is the least glamorous product on this site and one of the most reliably profitable, because the people who buy it are not shopping for fun.

The short version

What it is: a spreadsheet that shows someone where their money went, in under five minutes a month.
Who buys it: people who tried a budgeting app, found it fiddly, and went back to a notes file.
What to charge: £9–£19. Below £9 it reads as a freebie; above £25 you are competing with apps that have a login and a support team.
What decides whether it sells: whether someone can start using it in the first five minutes. Not the number of tabs.

Why this product, and not something more interesting

There is a version of this advice that says "build something you are passionate about". It is good advice for a hobby and bad advice for a first product, because passion does not tell you whether anyone will pay.

A budget planner passes a simpler test. People search for it every January and every payday. They already know they want one. They are not browsing for inspiration — they are looking for a tool, which means they are willing to pay for one that works.

The test that matters

Can you name three specific people who would buy this, and say what they would have used instead? If you cannot, the idea is not ready. If you can, you already know what the product has to do better than the alternative — which is the whole design brief.

Who actually buys a budget planner

Three groups, and they want slightly different things:

Buyer	What they are replacing	What they need
The freelancer with uneven income	A spreadsheet half-built in 2019	Months that do not assume a salary
The person who just got a pay rise	A notes app and a vague sense of dread	Categories that are already set up
The couple splitting bills	Arguments	Two people, one file, no maths

The freelancer is the one worth building for. They have money, they have a real problem, and there is no good free option — every free budget template assumes a regular monthly income, which is the one thing a freelancer does not have.

Write that person down before you open a spreadsheet. Every decision below comes back to them.

What you need

A spreadsheet app — Google Sheets is enough, and it is free
One month of your own bank statement, to check your categories are realistic
A way to write instructions, the same way you would write them to a friend
Somewhere to deliver the finished file — Unlockable is what this site is for, but the product works without it

Build it

Start with the categories, not the layout

Open a blank sheet and write down every category you spent money on last month. Not the categories a budgeting app would give you — yours. If "Coffee" is a real line in your life, it is a real line in the sheet.

Aim for 8–14. Fewer and the totals mean nothing. More and nobody fills it in twice.

Build the smallest version that works

Three columns and one row per category:

Category — the name
Planned — what you expected to spend
Actual — what you did spend

Add a fourth that subtracts one from the other, and colour it: over budget is warm, under is cool. That is the entire product. Everything else is a feature you can sell later.

Resist the second tab

The most common way this product dies is a v1 with twelve tabs, spending analytics and a savings goal chart. The person who buys a budget planner wants to know one thing — am I fine this month — and a twelve-tab file answers it more slowly than a four-column one.

Add the one thing apps do badly

This is what separates a template from a product. Pick one:

Irregular income: a "months until this runs out" calculation, so a freelancer can see how long a good month lasts.
Uneven bills: annual costs (insurance, tax, Christmas) divided into monthly set-asides, so December is not a shock.
Two people: a shared file with a column for who paid, so nobody has to reconcile anything.

One. Not all three. The one you picked is the reason someone chooses this over the next free template.

Write the instructions inside the file

A new tab called "Start here", three short paragraphs, and a note under each column header explaining what to type.

This is the highest-value twenty minutes of the whole build. A spreadsheet that needs an email to explain is a refund waiting to happen, and the buyer decides whether the product works in the first five minutes — before they have entered a single number.

Use it for a month

Fill it in yourself for one full cycle. You will find the things that annoy you: a category that never gets used, a formula that breaks when a cell is empty, a colour that makes an overspend look cheerful.

Nobody buys a planner that the seller clearly has not used.

Package it

Produce two files:

The planner — the spreadsheet itself. Clear it of your own numbers first, but leave one row of realistic example data so it does not open empty.
A one-page PDF guide — how to use it, and the two or three decisions the buyer has to make. Not a manual. One page, because it will be read once.

Name them so a stranger can tell them apart in a downloads folder. Budget Planner.xlsx is not as good as Budget Planner — freelancer edition.xlsx. The second one tells the buyer they bought the right thing.

What it is. A spreadsheet budgeting tool with a built-in guide, aimed at one specific money problem rather than at budgeting in general.

Who buys it. Freelancers with uneven income first — then anyone who has already given up on a budgeting app.

What you need. Google Sheets, one month of your own statements, and an afternoon.

What to charge. £9–£19. £19 is defensible if the irregular-income calculation is genuinely good.

Time to build. An afternoon for a version you would sell. A month of using it before you would sell it twice.

Price it

£9 to £19. The reasoning:

Under £9 it reads as a freebie, and people assume it is one of the twelve free templates they already skipped.
£19 is fine when the product solves a specific painful problem — the freelancer's irregular income — because they are comparing it to an afternoon of their own time, not to the price of a coffee.
Over £25 you are in the same bracket as apps with a login, an update cadence and a support inbox, and a spreadsheet loses that comparison.

There is more on this in the pricing guide, but the short version is that the number should be defensible in one sentence. "It costs £15 because it does the irregular income maths that free templates do not" is a sentence. "It costs what similar things cost" is not.

Deliver it

The delivery decision is the one most people get wrong, and it is worth more attention than the spreadsheet.

Emailing a file means it can be forwarded to anyone, and you have no idea how many people ended up with it. A marketplace means giving away 30% and being one listing among thousands. Hosting it yourself means building a checkout, which is a week of work for a product that took an afternoon.

What the file actually needs is to sit behind a link that:

Only works after payment. Not a link you send on trust.
Can be capped. By date, by number of unlocks, or by number of views — so a January promotion does not quietly become a permanent freebie.
Does not require the buyer to make an account. Every extra step between "I want this" and "I have this" loses people, and a budgeting tool is not something anyone is determined enough to fight a sign-up form for.

That is the whole of what Unlockable does, which is why the CTA above is a single link rather than a funnel.

Make the second version

The good news about a spreadsheet product is that the second version is much easier than the first, and it is a second product you can sell rather than an update you give away.

In rough order of what people will pay for next:

A yearly planner — the same sheet, twelve times, with an annual view. Sell it as the upgrade; existing buyers are the easiest audience you will ever have.
A freelancer edition — tax set-asides, invoices in and out, months until runway. This is a different product for a different person and can be priced higher.
A household edition — two people, shared costs, the awkward conversation about who owes what.

Each one took the same afternoon the first one did, and each one sells to an audience you already know how to reach.