See what your money becomes, before you spend it.
Type any price. CostMe shows what it would be worth invested at the market's long-run average. One honest number, then you decide on purpose.
Free on the web · works on any device · no ads · your data is yours
Thirty years. The same money, invested.
Real S&P 500 history, dollar-cost averaged. Not financial advice. Past results do not predict future returns.
Run your own number.
No account needed to look. Type something you almost bought this week and see its second number.
Try any price
EditableOr pick an example
in 30 years
Assumes 10% return, the S&P 500 historical nominal average (1926-2024), compounded monthly. Not financial advice.
Free · in your browser · no signup needed
One number that
stops the swipe.
Every price has a second version. What it would become if you invested it instead. CostMe shows that number for everything from a $4 coffee to a $4,000 trip, before you decide.
of decisions get a pause when the second number is on screen.
Watch your discipline
compound.
Every resist is a deposit you kept for yourself. The vault holds the running total and shows what it would be worth at a real return rate. Proof that not buying is a kind of buying.
a typical first-quarter vault, kept instead of spent.
Amy.
An advisor who never tells you what to do.
Amy thinks the purchase through with you and gives a real read. What you would give up, whether it is a use or an impulse, what to do instead. She advises; you decide. Calm, never preachy.
a second opinion in the moment you almost tap buy.
See the pattern
before it costs you.
Awareness Radar tracks when and where the urge shows up. Late-night taps, after-payday spikes, the categories that creep. It shows up as a quiet card on your home screen, not a notification you have to read.
Shipping with Profile and Context (V1.4).
Not a willpower app. A framing one.
CostMe does not ask you to want things less. It changes what a price means in the moment you reach for your card. Built on decades of behavioral-finance research, not vibes.
Citations and the full reasoning live on the CostMe blog.
Quiet wins, in the moment it counts.
“I closed the tab. The second number did what three budgeting apps never could. It made me pause without making me feel small.”
“Amy talked me out of a gadget I would have returned in a week, and into the trip I actually wanted. Calm, never preachy.”
“Watching the vault grow is oddly addictive. Not buying finally feels like getting something.”
Pro+ lifetime, for one payment.
Founders Lifetime is $149.99. Every feature Flint ships now and everything we ship later. After the first 50, Standard Lifetime takes over at $199.
One advisor, three depths.
Same Amy, same warmth. The tier sets how deep she goes and how long you have with her.
Jade
FreeFree
The full calculator and vault. Amy meets you with five thoughtful chats a day.
Opal
Member$7.99/mo
Amy unlimited. Chat as much as you want, with deeper analysis when a decision needs it.
Flint
Pro+$19.99/mo
Amy at her sharpest. Her deepest, most candid read when your decision warrants it.
About CostMe.
What is opportunity cost, and why does it matter?+
Opportunity cost is the value of what you give up when you make a choice. When you spend $200 on a jacket, the real cost isn't $200. It's what that $200 would be worth if you'd invested it instead. Over 30 years at the S&P 500's long-run average return (~10%), that $200 becomes roughly $4,000. CostMe shows you this second number before you decide.
Why does CostMe use a 10% return rate?+
10% is the historical long-run average annual return of the S&P 500 over the last ~100 years, with dividends reinvested. It's a widely cited benchmark in personal-finance education. If you prefer, you can set a more cautious or more aggressive assumption in settings.
Do I need an account to use CostMe?+
You can run a number on this page without one. A free account keeps your vault, goals, and Amy in sync across every device, and carries your tier with you. One signup, same Amy everywhere.
What plans are available?+
Three tiers, all built around the same Amy. Jade is free forever: the calculator, the vault, and Amy for five thoughtful chats a day. Opal at $7.99/month unlocks unlimited chat with deeper analysis when it counts. Flint Pro+ at $19.99/month is Amy at her sharpest. A web-only top tier is available for the decisions that warrant the deepest reasoning.
What data does CostMe collect?+
Your calculations, decisions (vault / 48-hour / bought), subscriptions you track, your conversations with Amy, and no-PII product-usage analytics. Stored so cross-device sync and your own tracking work. Encrypted in transit and at rest. No ad networks, no third-party tracking SDKs. Full specifics live in the privacy policy.
What devices can I use CostMe on?+
CostMe launches on the web, where we can refine every detail. Use it in any browser, or install it to your home screen on iOS or Android, where it runs full-screen like an app. Native apps arrive when the experience earns a place on your home screen. And your account, plan, and data are already there, waiting.
Try it tonight.
Next time you almost spend something, open CostMe first. One number that is the whole product.
Free · works on any device · 30 seconds to start