Track down old accounts
According to the British Bankers' Association, there is more than £15 billion sitting forgotten in bank and savings accounts in the UK, with the average balance estimated to be £600.
Using a website like mylostaccount.org.uk (mylostaccount.org.uk/) can help you access old accounts. The website is free to use and covers all UK bank and building society accounts. All you need to do is to go to the website and type in your details.
Money made: £600 found in an old savings account
Claim tax credits
It's always worth checking that you are receiving all the tax credits you are eligible for.
The handy website turn2us.org.uk (turn2us.org.uk/default.aspx) will do this for you for free. Simply enter your details and it will work out what you should be entitled to and tell you how to claim these.
Money made: For example, if you're over 60 you can claim for a free bus pass for travel during off-peak times.
Review your savings
If you've had the same savings account for a while it might be worth shopping around for a new account.
If you have a lump sum you are prepared to lock away for 12 months or longer, then a fixed-rate account might be best.
However, if you haven't yet used your ISA allowance for the current tax year then this sort of account should be the first home for any savings. You can save up to £15,000 each tax year in an ISA and this will not be taxed.
Money made: You could make about £25.50 over a year by switching £1,000 from an old 0.10% interest account into a savings account paying a rate of 2.55%.
Become a mystery shopper
If you're longing for some retail therapy but can't afford to hit the shops, why not earn a few pounds as a mystery shopper? Websites such as retaileyes.co.uk or mystery-shoppers.co.uk employ mystery shoppers to drop in unannounced in shops and restaurants and rate their experience.
After you send in your feedback, you'll be paid for your time and reimbursed for any purchases you made.
Money made: For a day's work expect to get around £20 and extra benefits like a meal for two thrown in.
Use cashback credit cards
If you pay off your credit bill in full each month, a cashback credit card could be the way to go. These offer you money back on purchases in certain shops or on goods such as petrol. For example the Santander 123 cashback card offers 3% on fuel spending (capped at £300 a month), 2% cashback on department store spending and 1% on supermarket spending.
See the top cashback credit cards with Moneywise Best Buys.
Money made: With the Capital One Aspire Elite card you'll get 5% cashback for the first three months (max. £200) with 2% cashback rewards thereafter.
Use cashback sites
You can earn even more money from shopping online. Cashback websites will automatically pay you every time you buy a product or a service from selected retailers, from your weekly groceries to switching your utility provider. Websites include topcashback.co.uk and quidco.com.
The top five cashback websites
Money made: Most cashback sites offer an average of 5% on purchases, so if you use them and spend £200 you'll get back £10. This won't be instant and the website vary with the timing on this but most take between one to three months to return the cash to you.
Take in a lodger
While most of us pay a fortune for our homes, it's possible to make your home make money for you. Under the government's ‘rent a room' scheme, you don't need to pay tax on the first £4,250 you receive either, which means you could charge up to £354.16 a month without being lumbered with a tax bill.
Money made: One small bedroom could make you around £289 a month and this rises dramatically if your home is in London.
Rent out a parking space
If you live close to a city centre, train station or football stadium and don't use your parking space or garage, you're sitting on a proverbial goldmine. Renting an empty parking place to a commuter or football fan could see you rake in the pounds. Parkatmyhouse.com is a website where you can advertise your space free of charge and let frustrated drivers get in touch.
Money made: A parking space in the West End of London, for example, can fetch £500 a month, while in a leafy suburb of Leeds a space could net you £100.
We're all guilty of hoarding items that "could come in handy one day".
But one man's rubbish could be another man's treasure, which is why online auction website eBay.co.uk is so successful.
If you don't want to pay eBay's fees than websites like preloved.co.uk or gumtree.com offer the same service but you'll have to arrange payment and delivery on your own.
Money made: eBay estimates the average British house has about £450 worth of unwanted items that could be sold on the site.
Car boot sales
If you'd prefer money in your palm instantly, a car boot sale is the place to go. Thousands of people flock to car boot sales every weekend, with pitches costing about £10 a day but don't expect to walk away with hundreds. Customers go to carbootsales to get a bargain and won't buy from you if you've overpriced your goods. To find out where to flog your booty, check out carbootjunction.com.
Make money from car boot sales
Money made: The average car boot sale table will make around £50 for a day but this is totally dependent on the quality of the stuff you're selling.
Recycle old mobile phone
If you've given your house a de-clutter there are bound to be lots of unused mobiles lying around. The price you can get varies a lot across websites, so use a comparison website like mobilephonerecycling.co.uk to find out where you can get the most cash first.
Make money from your old mobile
Money made: Recycle your old iPhone 5 (16Gb) for £105.04 with envirofone.com
Switch bank accounts
The high-street banks are crying out for our custom and many offer cash incentives to new customers. Switching is an easy process and the bank should be able to move over all your direct debit accounts automatically.
Money made: First Direct will give you £200 if you join and switch within 12 months.
Sell your skills
We all have skills and talents so why not use these to make a few extra quid. If you spent years of your life learning different musical instruments or a foreign language why not put these to better use. Prices vary but you could make around £60 for three hour-long sessions a week.
Money made: £20 per class
Surveys that pay
The web offers a wealth of balance-boosting opportunities. Survey websites such as yougov.com, panelbase.net and toluna.com will all reward you for your opinions, either through cash or reward vouchers.
Once you've registered on the website, you'll be sent surveys tailored to your personal profile, ranging from 10p to £2 per survey.
Money made: With Yougov you'll earn around 50 points per survey you take part in and when you reach 5,000 point you'll get a £50 gift voucher.