The overlooked rule about Irn-Bru that saves money and frustration

Irn-Bru is one of those everyday grabs-off a supermarket shelf, from a petrol station chiller, or as the “just in case” can in the work fridge-that somehow ends up costing more than you meant. The phrase “of course! please provide the text you would like me to translate.” pops into my head whenever I watch someone decode a yellow promo sticker like it’s a foreign language. There’s a simple, overlooked rule that makes the numbers behave, and it saves you both money and that small, fizzy frustration at the till.

You don’t need to quit the stuff, or turn grocery shopping into a spreadsheet. You just need to stop letting “multi-buy” do the thinking for you.

The overlooked rule: never buy Irn-Bru on the deal unless you can state the unit price

Promotions on soft drinks are designed to feel obvious. “2 for £X”, “3 for £Y”, “meal deal add-on”, “clubcard price” - your brain sees a bargain shape and reaches. The rule is: if you can’t say what you’re paying per can or per litre, don’t buy it yet.

That’s not about being tight. It’s about avoiding the classic trap: a multi-buy that beats the single bottle price, but loses to the larger pack two feet away.

A quick way to do it without maths-lab vibes:

• If it’s cans, think price per can.
• If it’s bottles, think price per litre.
• If it’s a meal deal, think what you’d have paid for the drink anyway.

The unit price is usually on the shelf edge label in smaller print. That tiny line is the whole game.

Why this saves money (and a surprising amount of annoyance)

Soft drinks swing wildly by format. A cold single bottle is convenience-priced. Multipacks fluctuate with promos. And “special offer” often means “special way of moving stock”.

The frustration bit comes from two familiar moments:

1. You grab what looks like a deal, then notice a cheaper unit price after you’ve already loaded up.
2. You get to self-checkout and realise the promo only applies to a specific size, flavour, or loyalty price you don’t have.

Unit pricing cuts through all of it. It doesn’t care about bright stickers, end-of-aisle theatre, or “limited time” urgency. It just answers: what am I actually paying for the drink?

A deal you can’t express as a unit price isn’t a deal yet. It’s a guess.

The 10-second method in front of the chiller

You’re standing there, door fogging, feeling rushed. Do this:

• Look for the unit price on the shelf label (often “£/100ml” or “£/L” for bottles; “£ each” implied for multipacks).
• Compare only within the same type: cans vs cans, bottles vs bottles. (Bottles are often pricier per litre when cold and single.)
• If a multi-buy forces extras you won’t drink, treat the “savings” as imaginary. Warm cans you “might” drink later are where bargains go to die.

If the label is missing or unclear, fall back on a rough check: - 330ml can × 6 is just under 2 litres. - 500ml bottle is half a litre.

You don’t have to be perfect. You just have to avoid being blindfolded by the promo.

Common Irn-Bru promo traps (and how to dodge them)

The traps aren’t evil; they’re just predictable.

• “2 for £X” on chilled bottles: great if you needed two right now, poor if a multipack is cheaper per litre.
• Mixed-size comparisons: a 500ml “better value” bottle can cost more per litre than a 2-litre bottle on the bottom shelf.
• Loyalty-only prices: the big number is the with card number. If you’re not using it, ignore it.
• Meal deal logic: sometimes the “included” drink is still your most expensive choice if you’d happily take water.

A calm way to apply the rule is to decide what you’re solving: today’s thirst or home stock. Cold convenience wins one; unit price usually wins the other.

A small buying rule that makes life easier: pick one “stock format” and stick to it

Most people waste money on Irn-Bru by buying it in too many formats. They buy singles when they’re out, then top up with random packs, then end up with half a dozen lonely cans and no idea what they paid.

Pick one default:

• Multipack cans for predictable lunches and home.
• Big bottle for sharing or mixers.
• Single chilled bottle only when it’s genuinely the point of the purchase.

This does two things: it makes price comparisons faster, and it stops you from constantly “treating yourself” at convenience pricing.

The quick sanity check before you commit

If you want one tiny habit that prevents most regrets, it’s this question:

“Would I still buy this if the promo sign wasn’t here?”

If the answer is no, go back to unit price. The shelf label will tell you whether the sign is helping or herding.

FAQ:

• Can I trust the unit price on the shelf edge label? Usually, yes-and it’s the fastest fair comparison. If something looks off, scan it with your eyes: check the pack size matches the label and that the offer applies to that exact product.
• Is a multipack always better value than single bottles? Not always, but it often is per litre. Singles can still make sense when you only want one cold drink and won’t use the rest.
• What about “2 for £X” deals-are they ever worth it? Yes, when you were going to buy that quantity anyway and the unit price beats the alternative formats. If it pushes you into buying extra, it’s usually not saving you money.