How to build a startup on a budget #
Most startup advice is written for people who just raised money. This site is for everyone else: founders paying for everything out of their own savings and trying to make those savings last.
Your runway is your savings divided by what you spend each month. For a solo founder with no revenue yet, nearly all of that spending is your own life: rent, food, getting around, and a stack of bills that renew every month. The cheapest way to buy more time to build is to make your life cost less.
That is what I do. My apartment in San Francisco would rent for $3,800 today, and I pay $1,680 a month for it. I do not own a car, which saves about ten thousand dollars a year in this city. I eat for free at tech events more often than I probably should, and getting to SFO costs me $2.05. I built the apps below on that budget, and the rest of this site explains how.
The apps #
Each card opens the app’s own page, which has the download links.
AI that runs on your phone #
Every app in this group runs its AI model on the phone itself.
Private AI Models
Chat with open models like Qwen and Gemma on your phone, even offline.
Private Transcribe
Whisper speech to text in 99+ languages. Works in airplane mode.
Secure AI
Ask questions about your PDFs and photos, answered by the model built into iOS.
Expose AI
Checks whether a photo, video, or link is AI-generated, without uploading it.
Insect Identity
Photograph a bug to get its name and whether it bites or stings.
Xin
An 18+ AI companion that remembers you, with the model running on your phone.Tools and trackers #
Credit Card Central
Tracks annual fee dates, sign-up bonus deadlines, and statement credits. No bank login.
Retire Goals
Log what you save and see the projected date you can retire. FIRE calculators included.
Mortgage Rate Tracker
Freddie Mac's weekly rates, plus a calculator that shows when a refinance pays for itself.
Election Tracker
US polls grouped by race, plus presidential approval, with a source on every screen.
Speedometer GPS
Your speed from GPS, with a speed limit alarm, HUD mode, and saved trips.
Sound Meter dB
A live decibel meter that shows how long each level is safe to be around.
QR Handler
Makes QR codes for links, WiFi, and contacts, and shows what a code holds before it opens.
Convert Units Calculator
140 units that convert as you type, including cups to grams by ingredient.
Pixelize
Turns photos into pixel art with 25 retro palettes, including Game Boy and NES.
Keep Closed
An encrypted vault for photos and files. One PIN opens it, and a second opens a decoy.
Fish Tank Tracker
Log water tests, track fish and equipment, and get a nudge before maintenance slips.
Homeschool Planner & Records
Plan lessons by child and subject. Attendance and hours add up as you check them off.
One Gym Man
A workout tracker where every new personal record knocks out a monster.
Work Capy
A focus timer. Leave the app twice and the capybara climbs out, ending the session.
Full Clear
A 30-day program, a panic button, and an urge log for quitting porn, all kept on your phone.Games and stories #
Capybara Crossing
Hop a capybara across roads, rivers, and railways, with 19 capybaras to unlock.
Chill Capy
A virtual pet capybara in a hot spring. He never dies and never guilts you.
Corgi Club
A virtual corgi that walks on your real steps and dresses for your real weather.
Kitty Kaboom
Slingshot cats at robot towers and collect ridiculous hats.
Bunny Bakery
A pixel-art idle bakery. Hire bunny bakers and befriend all 25 bunnies.
Frog Pond
An idle clicker. Hire worker frogs and migrate ponds for multipliers that never reset.
Merge Panda
Drop snacks in the crate, merge matching pairs, and work up to the Emperor Panda.
Flappy Kittens
Tap to fly a kitten through obstacles, collect coins, and unlock new characters.
Mafia Helper
Deals the roles and tracks the night for whoever is running Mafia or Werewolf.
Secret Fantasy
Romances told as text messages, where the replies you pick change the ending.
Omerta
A mafia romance told in texts, with three routes and a new episode every day.How some of them were built #
- An AI chat app that runs entirely on your phone
- A private speech-to-text app with Whisper
- A GPS speedometer, and why the hard part was lying less
- A credit card tracker without a server
Rent comes first #
Rent is the biggest line in the budget, so fix it before anything else. Mine is rent-controlled, which saves me about $25,000 a year, and no other tip on this site comes close.
- San Francisco rent control, from someone paying $1,680 for a $3,800 apartment
- Signing a lease in SF, including the deposit interest your landlord probably owes you
- How to furnish an SF apartment for almost nothing
Food #
San Francisco tech events will feed you if you show up and talk to people. The people are worth meeting anyway, and every so often one of them turns into a client or a cofounder. For the nights you cook, produce in Chinatown costs a third to a half of supermarket prices, and almost everything in the recipes comes from there.
- How to eat for free in San Francisco: the tech event circuit
- Grocery shopping in SF Chinatown, with the real price difference
- Is Costco worth it if you live in San Francisco?
- The Chinese pantry: twelve bottles for about $30, and the list every other recipe assumes
- Egg fried rice, the best use for leftover rice there is
- Wonton soup from the freezer, where one afternoon buys a month of six-minute dinners
Getting around #
A car in San Francisco costs $8,000 to $12,000 a year once you count parking, insurance, registration, and tickets. I do not have one.
- The real math on going car-free in San Francisco
- Muni, BART, and Clipper: which pass saves you money, and the 31-ride break-even nobody checks
- The $2.05 way to SFO: take SamTrans, not BART
- How to beat airline bag fees
- Cheap road trips out of San Francisco
The monthly bills #
Each of these is small, and each one renews every month whether you look at it or not.
- Cutting your PG&E, internet, and phone bills, about $1,740 a year from three phone calls and a form
- PG&E’s new $24 fixed charge, and why SF apartments get hit hardest
- Cheap dental, vision, and healthcare in San Francisco, worth reading if you quit a job, and its insurance, to build something
- Cut your own hair, since a $25 clipper pays for itself in one haircut
- Staying fit in San Francisco without a $200 gym
- Cancel Netflix: your library streams movies for free
All 23 articles in Frugal SF →
Building it for almost nothing #
The startup itself costs less than most people expect. Free hosting tiers are generous enough to run a real product on, a domain costs ten to fifteen dollars a year, and most AI work does not need a $20 monthly subscription.
- The free tiers I build on: Cloudflare, Vercel, Supabase, and the rest
- Stop paying $40 a month for AI: use GLM and Qwen instead
- Running AI models locally, free per use and private
- How coding agents work under the hood
- What a token is, and why it shows up on your bill
- What shipping six apps solo taught me, including where the time goes
Money #
Living off savings makes the boring parts of personal finance matter more. None of this is financial advice. It is arithmetic you can check.
- Where to keep your emergency fund, which is the same question as where to keep your runway
- How tax brackets work, and why a raise never lowers your take-home pay
- The HSA is the best retirement account almost nobody uses properly
- Why saving in your twenties beats saving twice as much in your thirties
- How to fund part of your life with hackathon prizes
- High-paying careers that do not require grad school, if you would rather fund the startup with a day job
AI #
Plain-language explanations of how modern AI works, for people who build with it and want to know what is going on underneath.
- How large language models work
- On-device AI: what it means and why it is suddenly possible
- Quantization, explained: how a huge model fits on a phone
- Fine-tuning vs RAG vs prompting, and which one you need
- What is MCP?
- The agent loop: how AI agents work
More on who I am and why I write this in About.