Thrifty Living: I can help you spot the bargains that turn into rip-offs

Way back in more innocent times, a purchase was a purchase. Even a discounted one. If you wanted a bargain, you sought it out and lo! it arrived, and you had the thrill of knowing that what you got was truly a money-saver.

Nowadays, things are a bit more complicated. If you want to cut down on the bottom line – and, in our credit-crunchy days, who doesn't – you have to have a Mastermind contestant-like grip on your transactions. At all times. Otherwise, what you will be handed is a great big rip-off. In my experience, rip-offs masquerading as bargains include the following:

1) "Pre-theatre" dinners, where the expected (and advertised) bill of £20 for dinner for two magically becomes a crippling £46 when the bill arrives. Silly you! You forgot to factor in the bread, mineral water and a "cover charge" – all not included in the bewitching offer.

2) Cheap travel tickets bought online that allow absolutely no latitude for human failings, acts of God etc. This week, I went to East Anglia to interview Louis de Bernières of Captain Corelli fame. Very pleasant it was too. I bought my train tickets two days prior to the journey, online; £12 each way, a bargain. Only my outward train was delayed because the brakes broke. I was therefore late for my stipulated return train and caught the next one, half an hour later. Hardly a problem, and certainly not my fault. Furthermore, as this was a mid-afternoon train trundling through Suffolk, it was about 10 per cent full. But hey ho, these modern times require up-to date policies. As I had not caught the exact train stipulated by my £12 ticket, it was rendered invalid by One trains. "Thirty-nine pounds please," said the ticket inspector with relish. Why? Why did I have to buy another ticket when I was holding one in my hand for the day and journey in question? How can a replacement ticket for exactly the same service justify this huge increase? Because the company says so. I didn't give him the satisfaction of a row, but handed over my credit card, seething and pretending not to care.

3) So-called loyalty cards. "Have you got a Nectar card?" says the person at the till. "No," I say. What I do not say is: "And I never will have one, because they are a total rip-off." Nectar! The name implies a naturally sourced delight. The reality, my friend, is that a Nectar card, or any of its many rivals, will encourage you to buy all sorts of unnecessary stuff to build up points. After about half a century, you venture to cash in your points. Sucker! All you are qualified to purchase is half a bottle of Liebfraumilch, or a pair of driving gloves, or a plant pot. Nectar cards; they are the Green Shield Stamps de nos jours, and we all know what a bargain those little gems were.

4) Waitrose. Fairly obvious, this. Waitrose presents buying three cartons of juice for a fiver as a tip-top bargain. That is about the only thing of value you will find within these walls. Oh, there's heaps of lovely food, but no bargains. Waitrose is the only part of the John Lewis Partnership where the famous "never knowingly undersold" slogan obviously does not apply, as this food can be undersold everywhere bar Harrods Food Hall.

5) Telephone, broadband and cable "bundles". Inordinately complicated with a mesmerising array of money-saving "tariffs" that look fantastic on a poster outside the shop – but once said bundle is bundled into your house, your bill is inexplicably larger than ever. How can this be? Could it be because you are daring to use your phone during the hours of daylight?

6) Wire baskets at Boots. Empty and stacked, they seem innocent enough. But, as an executive from Procter & Gamble told me at the Baftas (I know, my life!), these baskets have a purpose. Procter & Gamble call it something like "positive" shopping. I call it a drifting intent to buy, armed with basket. You simply wander up and down the aisles slinging in Procter & Gamble products such as Nicky Clarke hair gel and Vaseline lipsalve and that must-have Boots No 17 anti-wrinkle cream. Before you know it, you've racked up £30. Entering "best value" Boots with no list and a basket – fatal.

And so it's lists from now on. Lists, and better time-keeping, and close reading of the small print, and a determined vigilance to beat the shops, internet ticket providers, telephone companies and the rest of the wily bunch at their own game.

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