Track 2 · Real-Life Money → Phase 13: Big Money Decisions
Big purchases: how to decide
For anything over about $500, five questions turn an impulse into a decision: cost-per-use, a wait scaled to the price, whether your emergency fund survives it, sinking fund vs. financing, and what else the money could do.
The situation
The thing costs $800. You’ve watched the reviews, you’ve imagined owning it, and the site says the sale ends tonight. Your thumb is hovering over Buy Now. This is the exact moment this course has been building toward since the 24-hour rule in Phase 4 — because everything over about $500 deserves more than a hover. It deserves five questions.
The idea
Here’s the reusable decision frame. For anything over about $500, ask all five — in order:
1. What’s the cost-per-use? Divide the price by the number of times you’ll honestly use it. This one question separates bargains from regrets, and it has nothing to do with the price tag.
2. Have I waited long enough? Scale up the 24-hour rule from lesson 4.6: wait about a week for every $500 of price. An $800 purchase earns a week and a half; a $2,000 one earns a month. “The sale ends tonight” is a pressure tactic, not a deadline — there is always another sale.
3. Can my emergency fund survive it? If buying this would leave your starter fund (lesson 5.2) gasping, the real price includes the credit card interest on whatever emergency comes next. A want that consumes your safety net isn’t affordable yet.
4. Sinking fund or financing? If the answer is “finance it,” pause: financing a want adds interest — the enemy face of compounding from lesson 6.7 — so the same item simply costs more. A sinking fund (lesson 4.5) buys the identical thing at sticker price; the only cost is patience.
5. What else could this money do? The opportunity-cost question. This $800 could also kill a chunk of high-rate debt, top up a goal from lesson 5.5 — or start growing for future-you, which is exactly where this course goes next, in Growing Your Money. The question isn’t “never spend.” It’s “is this the best job I can give this money right now?”
The rule of thumb: a purchase that passes all five questions is a decision. One that can’t survive them was an impulse wearing a decision’s clothes. And passing means buy it — guilt-free, because you did the math the marketing hoped you’d skip.
By the numbers
Cost-per-use math on the same $300 item, two different lives — illustrative round numbers:
| The $300 thing | Times used | Cost-per-use |
|---|---|---|
| Used every week for 3 years (156 uses) | 156 | ~$2/use |
| Used twice, then a shelf ornament | 2 | $150/use |
Same price tag, 75× difference in what it actually cost you. That’s why question 1 comes first: a $300 item you’ll use weekly is cheaper per use than a $40 one you’ll use once.
And the wait, scaled:
| Price | The wait it earns |
|---|---|
| $500 | ~1 week |
| $1,000 | ~2 weeks |
| $2,000 | ~1 month |
If the want is still alive after the wait, it was probably real all along — buy it with a clear head (and ideally a sinking fund). If it quietly died, the wait just earned you the full price back.
Where this fits
That closes the decision frames: a lease you can read (13.1), a car you can price (13.2), a move you can fund (13.3), a someday-home you can discuss calmly (13.4), and now a five-question filter for everything else. One arc remains in this course — the money you don’t spend, and how it grows. Phase 14, Growing Your Money, brings the snowball from Phase 6 back one last time — finally working for you.
Do it
Take the biggest purchase you're currently considering and run it through all five questions on paper: cost-per-use, the scaled wait (a week per $500), the emergency-fund check, sinking fund vs. financing, and the opportunity-cost question. Whatever the answer turns out to be, you'll know it was a decision — not an impulse.
Check yourself
1. What is cost-per-use math?
Price alone says nothing about value. The same $300 is a bargain at $2 per use and a waste at $150 per use — the honest question isn't 'can I afford it?' but 'how often will I really use it?'
2. How does the 24-hour rule from lesson 4.6 scale up for big purchases?
The bigger the price, the longer the cooling-off period it deserves. Most of the urgency you feel at $1,500 is manufactured by marketing — if the want survives three calm weeks, it's probably real.
3. The new purchase would drain your emergency fund to almost nothing. What's the move?
If buying the thing means one car repair would land on a credit card, the real price includes the interest and stress that follow. A want that requires your safety net isn't affordable yet — a sinking fund gets you there safely.
4. Why does 'sinking fund vs. financing' matter for a want?
Saving first (lesson 4.5) means paying exactly the sticker price. Financing means paying sticker plus interest — the enemy face of compounding from lesson 6.7. For needs, financing is sometimes unavoidable; for wants, it's paying extra to skip the wait.
5. What's the opportunity-cost question?
Every dollar spent on one thing is a dollar that can't do anything else — pay down a debt, pad a goal, or grow over time. The question isn't 'never spend' — it's 'is this the best job I can give this money right now?'
Keep this
Five questions for anything over ~$500: (1) what's the cost-per-use? (2) wait a week per $500, (3) can the emergency fund survive it? (4) sinking fund or financing — financing a want adds interest, (5) what else could this money do? A purchase that passes all five is a decision, not an impulse.