Spending & saving
Discount maths, unit prices, subscriptions, budgets and emergency funds — the money that moves every week.
Games in this section
What it covers
- 1What a discount, a bundle deal and a stacked coupon are really worth
- 2Unit price: the bigger pack is not automatically cheaper
- 3Subscriptions and sunk cost: the annual total nobody adds up
- 4Monthly budget splits and savings rate
- 5How many months of expenses an emergency fund should cover
- 6Impulse triggers and the cooling-off window
Quick check
Three questions from this section.
Coming soonOpens with this section's first games.
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Coming soonQuestions people ask
Is 'buy one get one half price' a good deal?
It works out to 25% off across two items, so it only saves money if you were buying two anyway. Adding a second item to unlock it increases what you spend.
How do I work out the percentage off?
Divide what you pay by the original price and subtract from one. Paying £150 on a £200 item is 25% off. Reverse it by multiplying the original by the remaining fraction.
Is the bigger pack always cheaper?
No. Compare unit price — total cost divided by quantity or weight. Promotions regularly make the small pack cheaper per unit than the family size.
How much should an emergency fund be?
Three to six months of essential expenses is the common range, and six to twelve if your income is irregular. The variables are your fixed monthly costs and how long a job search takes in your field.
How should I split my monthly budget?
A widely used starting point is 50% needs, 30% wants, 20% saving and debt repayment, adjusted for how much of your income rent takes.
How much do subscriptions cost per year?
Multiply each monthly fee by twelve and add them up. Five services at $10 a month is $600 a year — usually more than people estimate before they count.
How do I stop impulse buying?
The single most effective habit is a forced delay: put the item in the basket and decide later. Most impulse urges drop noticeably within that window.
What is a savings rate and what is a good one?
Savings rate is the share of take-home pay you keep. It matters more than investment returns early on, because it is the one input you fully control.