Picking a credit card is a chore that people put off for years. The comparison sites are cluttered, the terms are written by lawyers, and every result feels like an ad, because it usually is.
What people actually want is a short answer to a specific question. Which card makes sense for me, right now, given my credit score and what I am about to do with my life?
The idea: a credit card rate comparison built in Google Sheets that filters down to the cards a person can actually get and would actually use. It is one of the 100 business ideas in Google Sheets on my list, and one of the few where the sheet can make money even when it is free.
The idea
Compare the credit card options available in the market. For each card, record interest rates, fees, rewards, and the unique benefits it offers. Then let users compare cards based on their own needs rather than someone else's ranking.
The angle is timing. Help users find the right card for the right moment in their life. Someone starting a business needs different things from someone saving points for a big trip, or someone trying to pay down a balance. Finding the best card for that moment is pure gold to the person searching, and they will remember where they found it.
This kind of sheet can also rack up affiliate fees for a new, growing business. Card issuers and comparison networks pay for referrals. A sheet that sends people to the right card with a tracked link is a small affiliate business with almost no overhead.
The feature that sets it apart: include the credit score requirements for each card, and let the user enter their score. Now the sheet only shows cards they are likely to qualify for. Make it super easy for them to know what is available to them, and only them. Nobody else does this well, because the comparison sites want to show every card they get paid for.
One thing to be honest about with buyers: rates and offers change. The sheet is only as good as its last update. That is a burden for you, and it is also the reason people will pay for it more than once.
How to build it in Google Sheets
- Cards tab. One row per card: Card Name, Issuer, Purchase APR, Balance Transfer APR, Annual Fee, Intro Offer, Rewards Type, Rewards Rate, Category Bonuses, Foreign Transaction Fee, Minimum Credit Score, Best For (business, travel, cash back, balance transfer, building credit), Link, Last Updated.
- Finder tab. Three input cells: the user's credit score, their goal, and their rough monthly spend. Below, the matching cards sorted by rewards rate.
- Calculator tab. Pick a card, enter spend by category, and see estimated yearly rewards minus the annual fee.
- Glossary tab. Plain-English definitions of APR, grace period, balance transfer, and the rest.
The features that make the Finder work:
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FILTER and SORT together.
=SORT(FILTER(Cards!A:N, Cards!K:K<=B2, Cards!L:L=B3), 8, FALSE)returns every card whose minimum score is at or below the user's score, matches their goal, and sorts by rewards rate, highest first. - Data validation dropdowns for Best For on both tabs, so the goal filter always matches.
- Conditional formatting on the Cards tab that flags rows where Last Updated is older than 90 days. This is your own to-do list.
- Checkboxes in a column called I Have This, so the user can hide cards they already carry.
- Protected ranges on the Cards tab, since one mistyped APR in a sold copy undermines the whole thing.
- Publish to web for a read-only version of the Finder you can embed on a blog page as a free preview. The full sheet, with the calculator and the links, is the paid product.
Keep the Cards tab honest. Only enter figures you have checked on the issuer's own page, and record the date you checked.
Who pays for it, and how to sell it
There are two ways to make money here, and they are not exclusive. The affiliate route: the sheet is free or cheap, and you earn when someone applies through your link. The product route: personal finance bloggers, coaches, and small credit unions buy the sheet to use with their own audience, with their own links in it.
The end user is paying for the filtering and the calculator. The blogger or coach is paying for a finished tool they would otherwise spend a month building, and for the updates.
Because the data goes stale, a subscription is the right shape for the paid version. Sell a one-time copy for people who want a snapshot, and a yearly plan for anyone who wants the rows kept current. A service on top is a natural fit too: a paid session where you walk someone through the Finder for their situation, though be clear that you are helping them compare, not giving financial advice.
Gumroad works for the one-time copy. For the updated version, OnlySheets sells access to the live Google Sheet and shares it automatically with every paying customer, so each update you make reaches all of them at once.
First 10 customers: write one useful post for one life moment. "Cards to look at when you are starting a business" with the Finder embedded and only the relevant rows visible. Share it in a community for people in that moment. The first ten come from the people who want the calculator and the rest of the rows.
Related ideas from the list
- Affiliate Marketing Link Tracker, which you will need the moment this sheet starts earning referral fees.
- Niche Affiliate Hunt List, the same affiliate mechanic applied to finding programs worth joining.
- Budget Planning Model, which sells to the same personal finance buyer and pairs well with a card comparison.
Want the other 99? This is one idea from my list of 100 business ideas you can build in Google Sheets. Get all 100 business ideas as a free Google Sheet.
And if you want to learn how to package and sell spreadsheets, my course Selling Spreadsheets walks through exactly that.
