I phoned my friend Toby the other day. "I can't talk now, I'm on an assignment," he growled into the phone. "It could blow my cover."

For Toby, working as a mystery shopper is a very serious business, and not just a way to make money in between acting jobs.

Luckily, he also finds it quite good fun and a chance to play James Bond.

He has occasionally had to pretend to be partially sighted to test whether supermarkets have their pricing in an accessible form and what kind of service he gets from the staff, which he found really interesting.

Mystery shopping is a great way to earn a living for people with unpredictable patterns of employment.

I don't know if you've noticed, but a whole bunch of new websites have sprung up recently, claiming to harness the power of 'collective buying'. You might have seen we told you about one of these websites recently.

Essentially what they mean is that they use bulk buying to give you a discount. Nothing particularly new or clever then right? Actually, the theory behind these sites is so brilliantly clever and simple you'll wish you'd thought of it yourself.

Want money off your purchases at high street stores and restaurants such as Dorothy Perkins and Carluccio's?

How about if all you had to do to get the discounts was to show the waitress or sales assistant your mobile screen?

If that sounds tempting, the good news is that you can now sign up for digital discount vouchers that are downloaded direct to your iPhone, with similar applications planned for other mobiles soon.

Nationwide is offering £75 cash to existing Flex Account customers who make the account their main current account.

The UK's largest society is thought to be targeting the throngs of consumers who have the account for its overseas spending perks but do not widely use it otherwise.

Hey, that's me! I opened a Flex Account a few years ago and take the cash card on holiday with me to benefit from fee-free spending overseas. However I rarely use the account for day-to-day spending or direct debits or standing orders.

So, is it worth making Flex Account my main current account?

For frequent flyers, a free upgrade to business class is the holy grail – albeit one glimpsed from time to time.

Most people report being upgraded only when the airline has made a mistake with the booking or overbooked economy class and need the space.

Even then you will be in competition with all the other passengers. So the best way to be bumped up is to look the part – both on the booking and in person.

Earning money is so overrated. You get much more sense of achievement when you just sit back and let someone else do all the hard work, then plonk £100 in your bank account for nothing.

Luckily, you can do just this with a number of bank accounts which are offering you cash just for the effort of opening them and transferring your salary, standing orders and direct debits.

First Direct 1st Account
The phone-and-internet bank First Direct is giving away £100 with its current account. If you deposit £1,500 per month for the first three months, £100 finds its way onto your balance sheet. But if you open the account and neither put the £1,500 per month into the account nor maintain an average balance of £1,500, you will be charged £10 per month. At least you get a free £250 overdraft.

If you don't like the account and switch away within 6-12 months of opening it, you get another £100. Bonus.

If you enjoy going to the cinema as much as I do, it can become an expensive habit. The tickets alone don't come cheap, and by the time you've paid for a drink and popcorn or sweets as well, the costs stack up.

So if you're a big movie fan how can you go to the cinema for less?

Marks & Spencer has jumped on the green bandwagon by launching a new Home Energy Service division. Staff will be among the first to benefit - the company is offering free loft or cavity wall insulation to all its employees.

If all staff take up the offer, M&S will insulate over 30,000 homes for free, leading to an annual saving of 13,000 tonnes of carbon dioxide.

So what is involved, and what other unusual staff perks are around?

Girls love to shop. It's less of a stereotype, more a generally accepted rule. With the recession hitting everyone's wallets, even shopaholic ladies have had to make cut backs though. And you'd be surprised to know the things they are cutting back on.

A study by the Co-Operative Bank found that women are OK with reigning in spending on clothes, fashion accessories and eating out, but they refuse to cut back on the finer things in life; nice food, good wine and presents for others.

So what does all this mean for our finances, and how can we still enjoy a little of what we love without spending a fortune?

It's that time again - a week of having the kids at home and desperately trying to keep them entertained without spending a fortune. If you're not going on holiday - and lots of us can't afford to - you'll need to have a load of good ideas that'll keep them occupied come rain or shine.

So here are a few suggestions to get your started, and best of all they're all dirt cheap.