Erika Kullberg’s apps

50/20/30 Budgeting App

Track spending against the 50/20/30 framework.

The framework everybody quotes, actually enforced: spending sorted into the three buckets automatically, with the split shown against the target and the gap named. It works out where the ratio breaks rather than only that it did.

What a v1 does5 features
  • Automatic sorting into needs, wants and savings
  • This month's real split against the 50/20/30 target
  • The categories pushing the ratio out, named
  • The ratio the current income can realistically hit
  • Trend over months, not a single verdict

The market

Proven marketBudgeting apps
10M membersat Rocket Money, which charges for budgeting and bill management

Monarch has roughly 1.8M monthly users and YNAB about 1.4M, at $99.99 and $109 a year. Mint's closure left the largest gap in consumer finance and three paid products grew into it. This is costed at $6 a month.

Where these numbers come from
CompanyEarnsReachSource
Rocket Money$880M+ saved for members10M+ membersCompany-stated, 2025
Monarch Money$99.99–199 a year~1.8M monthly active usersPublished pricing, 2026
YNAB$109 a year~1.4M monthly active usersPublished pricing, 2026

Why this audience

This is the audience that has been taught the framework by name and applies it by estimate. They already believe in the split. Enforcing it automatically against real spending is the difference between knowing the rule and following it.

Before it can launch

  • Open-banking access through Plaid

What it earns

Drag me Every figure recalculates as you go.

Paying users1,000

0.0047% of 21.2M followers · capped at 50,000

Price per month$6

Opens on the price this idea was costed at, $6.

1,000 paying — 0.0047% of 21.2M followers — × $6 a month = $6,000 a month

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Revenue a month$0123456789,012345678901234567890123456789
Over twelve months$01234567890123456789,012345678901234567890123456789

Fifty thousand paying users is the ceiling every one of these pages is drawn against, not a forecast. It opens at a thousand, the bottom of the range, so the first figures you see are the modest ones. What the cap buys is comparability: the same range on every app, and the percentage of the audience it takes as the number that moves.

Is this the one for your audience?

We fund it, build it, and run it. You bring the audience and take a share of the revenue. Nothing to pay and nothing to build.

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