Wow! Never saw this.
How about:
Get a cashback credit card, pay off the full amount every month. Keep your money in a high interest current account that calculates interest daily.
Result: Your money spends longer in the high interest account, so you are paid for keeping it in there and only clearing the balance towards the end of the month. You are also paid ~1% cashback for spending the cash on the credit card. No fees since you pay it off before month end. Hence you receive interest for not spending your money, and cashback for using the credit card. That's an arb I think?
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Another: (And I've made ~£1000 with this one)
My local charity shop at my old house was run by the local hospice. They rented a large industrial unit and hence had massive floor space and people used to do house clearances and drop their stuff off there. It got so many donations every day that they could price everything really cheaply and not spend much time checking it. Hence their books were all priced at 25p for paperback and 50p for hardback. I could go in on any given day and buy 4 or 5 books for £2 tops and sell them on Amazon for £20-£50. The best I ever did was a 25p book that was out of print and which I sold on for £26. Also got Japanese Candlestick Charting, The Intelligent Investor, Education of a Speculator and about 4,5 more that I kept in my personal collection.
I also bought a job-lot of 20 trading books for £100 once - sold about 10 of them for £150 and kept the rest!
Non fiction is best..... Do NOT buy the Da Vinci Code for 25p and expect to shift it at profit! Trading books are excellent for this - especially if you know they are good ones. worst case scenario: you don't sell it, waste 25p and give it back to the charity shop.
Although I've been told you can get a free trial franking machine for 30 days if you're planning a clearout.....
again, i think this is arb...
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Another:
Get 2 spread betting accounts with the free £100 starting offer - loads of these available.
Pick an instrument to trade (e.g. FTSE)
Go long on one of them with £100 profit target, £100 SL (OK - lave a bit either side for spreads - say £90). Go short on the other. You will end up with one account where you've lost the £90-odd quid, which wasn't yours anyway, and another that now contains £190 and you can draw out the £90 and spend it on w@nkmags!
So these are all fairly simple little swindles and I'm sure everyone knows about them. They all take a bit of time to do, but the credit card/bank account one is an absolute must. I have been doing this for years. It's only like £10-15 per month but so what it's free cash for very little effort. you can set up the credit card payment by DD and never reap a late fee.
Then there's the option of buying expensive things, taking them back for a refund and still reaping the cashback award!
Oh yeah and Clubcard points - Pick up the receipts everyone dumps around the self-service till and claim them on your own card!! That's a bit of a pikey one for 1 or 2p here and there though!
What about bank accounts with an opening bonus (Free money - and refer a load of mates too to get referral bonus!)? Interest-free overdrafts (Put the overdraft cash into an interest-paying account)?
All I can think of atm - but used all of these in the past.