Big companies use a variety of ways to make money - here's seven ways to turn the tables

A company’s job is to make money, nowt wrong with that, but our job is to keep it. Some firms use a host of tricks to keep us in the dark, yet if you can uncover their secrets you can win.

Their techniques are wide and varied. One example is 'price differentiation', where they aim to charge each customer as much as they'll pay - often done using 'white labels', where the same thing is sold under different names. So here’s 7 tricks to turn the tables…

1. British Gas customer? It also operates under the name Sainsbury's Energy but there it's £200/year cheaper. British Gas runs Sainsbury's Energy for the supermarket, yet there you pay it far less. Based on a year’s typical dual fuel usage...

- On British Gas’ standard tariff you pay an average £1,154.

- On British Gas’ Price Promise March 2016, its cheapest deal, you pay average £1,100.

- On Sainsbury Fixed Price March 2016, you pay average £950.

Sainsbury's Energy does have separate call centres, but it's still operated by British Gas and while like many energy firms it gets its fair share of complaints, in my most recent poll 43% rated its service 'great', British Gas 37%.

So if for some reason you're brand loyal and want to stick with British Gas, huge savings are still possible. However, as always price varies by region and usage, so do a comparison to see how it stacks up for you via my www.CheapEnergyClub.com (where you also get switching cashback) or any www.ofgem.gov.uk approved comparison site.

2. Zara sells its clothes at a fraction of the price. If you’re one of millions planning a trip to Spain this summer, you may want to stop shopping at Zara here right now. Spain is Zara's home country and it sells its clothes at vastly lower prices there. Better still, the www.zara.com Spain website has an English language option, you can compare prices before you go (you can’t order UK delivery from it).

Clothes there are often cheaper in euros than in pounds, even before the currency conversion. For example a jacket with piped pockets I found is £129 in the UK but just €99.95 in Spain, which after conversion is just £72. In fact on a basket of goods it was on average 38% cheaper.

Some of you may think ‘ah yes I’ve seen the euro price on some labels in the UK’, but that’s usually the French price, which is generally more expensive. This trick works for others in the same group, Massimo Dutti, Pull & Bear and Uterque.

3. If a loan's advertised at 3.9% rep APR, they're allowed to charge 20%. Every loan these days is listed as a 'representative' or 'rep' APR - that means by law only 51% of accepted applicants need to get the advertised rate. The rest can be and usually are charged more, and there's no cap on how much more. Worse, the only way to know is to apply, and that leaves a footprint on your credit file. So be very careful.

One way to mitigate this somewhat is to use the calculator at www.mse.me/eligibility which tells you your odds of being accepted without marking your credit file. The higher your acceptance odds the more likely you are to get the advertised rate, although it’s not guaranteed.

4. Amazon shopper? You're entitled to music going back 16 years. If you've bought CDs or vinyl, you're entitled to the downloads for nowt going as far back as 1999. To be fair Amazon doesn’t hide that you can do this, but it’s a good trick.

Just login to your www.amazon.co.uk music library to see if you’ve any past tracks available.

As JHL1959 told me: "Crikey, it's given me 182 albums, that's 2,367 tracks. Amazingly, I still like a lot of them - cheered me up."

It’s not always such a success though, GingerJuice said: "Just did this - thought it was brilliant then realised I'd bought the mother-in-law the Susan Boyle CD last year... ugh."

5. Only get good mobile signal with one network? Switch to a piggyback. Many people tell me "I wish I could switch network but only Vodafone/EE works in my home." Yet there's a way to switch provider but keep the same signal...

Only EE, Vodafone, Three and O2 are actual mobile networks, yet there are many cheap virtual networks piggybacking on the same signal. E.g. Giffgaff is O2, Asda is EE, TalkMobile is Vodafone and Shebang is Three (full piggyback list at www.mse.me/piggyback). So check which other providers piggyback on your existing network and see if they’re cheaper.

6. Energy firms can't charge exit penalties within 49 days of a fix ending. If you’re on a cheap fixed energy deal you needn't wait until the last day to switch to avoid exit fees as rules state that 49 days before your fix ends, you're allowed to switch without penalty.

7. Play the codeshare trick - where two airlines sell the same flight. Airlines don't shout that their partners often sell their flights too, sometimes for less.

If you're going on popular long-haul routes this can be a way to save. Eg, a return Delta flight from Heathrow to New York over Easter costs £631 - but the same booked as 'Virgin Atlantic' is £549.