- The Money Dad
- Posts
- The $100 Rule: How I Decide If a Purchase Is Worth It—And Teach My Kids to Do the Same
The $100 Rule: How I Decide If a Purchase Is Worth It—And Teach My Kids to Do the Same
Discover The $100 Rule—a simple, powerful mindset to help you and your kids make smarter spending decisions. Learn how to evaluate purchases and build lifelong money habits with humor and intention.
Kevin Murray
May 15, 2025
In partnership with
Money Dad’s Family Financial Fuel
Join 400,000+ executives and professionals who trust The AI Report for daily, practical AI updates.
Built for business—not engineers—this newsletter delivers expert prompts, real-world use cases, and decision-ready insights.
No hype. No jargon. Just results.
It’s shockingly easy to spend $100 these days.
One Target run.
Two medium coffees, a tank of gas, and a pack of gum.
A few clicks on Amazon when you're half-paying attention during your kid's lacrosse practice.
Poof. Gone.
But over the years, I’ve developed a simple mental filter—what I call The $100 Rule—that helps me make smarter spending decisions. And it’s become a go-to tool not just for my own purchases, but for teaching my kids how to evaluate money choices with intention.
What is The $100 Rule?
It’s painfully simple:
“Would I still want this if someone handed me $100 in cash and said I could either keep the cash or buy this thing?”
That’s it. No spreadsheets. No budget apps. No guilt.
If I’d take the cash—game over. Not worth it.
If I’d gladly give up the cash—okay, now we’re talking.
This one little question injects some much-needed friction into impulse spending. And it turns out, friction is our friend when it comes to keeping our bank account from looking like a tumbleweed blowing through a ghost town.
How It Works in Real Life
Let’s say I’m eyeing a $95 pair of “performance joggers” online.
They promise to wick sweat, attract compliments, and maybe even turn me into the kind of dad who drinks green smoothies and stretches after workouts.
Before I hit Buy Now, I stop and imagine someone holding out a crisp $100 bill and saying:
“Here you go. Take this, or you can have the joggers. But not both.”
Nine times out of ten, I’ll take the cash. Why? Because deep down I know:
I already own three pairs of joggers.
None of them have turned me into an Instagram fitness dad.
And green smoothies still taste like liquified yard clippings.
How I Teach This to My Kids
Money lessons with kids have to be bite-sized, real, and occasionally hilarious.
Here’s how I break it down with my 13-year-old daughter and 15-year-old son:
“If I gave you a $100 bill, would you rather have that Fortnite skin or the actual money in your hand?”
They pause. They squirm. They do a mental backflip.
Sometimes they still go for the skin. But sometimes—they surprise themselves and say, “I’d take the money.”
Boom. That’s a win.
They’re learning that money isn’t just for spending—it’s a tool for choice, freedom, and yes, even power. (Supervillain laugh optional.)
When to Break The Rule
Okay, I’ll admit it: The $100 Rule isn’t perfect.
Sometimes, the value of a purchase isn’t clear until later. Like that $120 massage I got after tax season that saved my spine. Or the used treadmill that cost $80 but now powers half my stress relief.
And sometimes the “money or the thing” decision needs context. Like:
Is this a one-time opportunity?
Does this align with my goals or values?
Will I still be glad I bought it in a week?
(If it’s just “because it’s on sale,” that’s a red flag. Discounts don’t make dumb purchases smart.)
Final Thoughts From The Money Dad
The $100 Rule doesn’t solve every financial dilemma. But it’s a powerful gut-check.
It forces you—and your kids—to make spending intentional. And in a world that’s trying to convince us that “add to cart” is a hobby, that’s a superpower.
So next time you’re standing in a store, hovering over a checkout screen, or talking to your teen about why they don’t need their 7th pair of sneakers, try this:
Hold up that imaginary $100 bill and ask:
“Would I still want this… or would I rather keep the cash?”
Your bank account will thank you.
And so will your future, slightly wiser self.
Want to teach your kids more practical money lessons (and maybe pick up a few for yourself)?
Subscribe to The Money Dad newsletter—real advice for raising money-smart kids without being a boring finance guy.
We’re excited to announce The Money Dad Referral Program! Share your unique link with friends and family, and earn exclusive rewards like our Creative Tax Strategies for W2 Employees guide, coaching calls, and more as a thank-you for helping grow our community.