Grab top-secret theatre tickets from £4, including West End shows... but only if you can keep your mouth shut

It's the top-secret trick that theatres don't want you to know exists. Welcome to the hush-hush world of last-minute seat-filling, where it's possible to watch a show from as little as £4. Theatres do it because they quite literally need bums on seats – but you must agree not to say what you get so you don't upset people who pay full whack.

13 ways to use less plastic AND save cash

Plastic waste continues to make headlines, with Scotland planning to charge a 20p deposit for plastic bottles and Morrisons doubling the price of reusable plastic bags. And it's with good reason – shockingly, the Ellen MacArthur Foundation predicts there will be more plastic than fish in the oceans by 2050.

How I built my own DIY pensions dashboard

What's the best way to work out if you'll have enough pension when you retire? Start by finding out what your retirement nest eggs are currently worth. It can be a challenge keeping track of the different pots of pension cash you accumulate over your working life, so here's how to use a simple spreadsheet to see at a glance how much pension you've built up so far.

We test eBay vs Facebook selling prices – which wins?

Second-hand selling used to be all about eBay, but now local Facebook selling groups and the social network's Marketplace are hot on its heels. With Facebook, the best bit is there are NO fees, so you keep all the profit. Yet with eBay, you've a wider audience, as most Facebook sales are local.

The MoneySavingIdiot tackles travel: 'I basically felt like a cross between Martin Lewis and Michael Palin'

If you missed my debut MoneySavingIdiot blog from last month (on claiming for a train delay), first of all – how dare you. Secondly, the basic premise is that while I help people save money every day by writing for MSE, I'm not always so clever when it comes to my own cash, so I'm sharing my quest to be better with it in the hope of inspiring other non-natural MoneySavers. This week: travel tips. 

Ryanair's app now measures luggage – but can it really help you obey its strict bag rules?

Budget airline Ryanair has launched a new 'bag sizer' tool on its iPhone/iPad app, which scans your hand luggage to check whether it fits within its strict measurements.

To 100 and beyond… now you can get a mortgage that lasts until you die

Have you imagined reaching the age of 100? Quite possibly. But could you imagine still paying off a mortgage worth tens or hundreds of thousands as a centenarian? Possibly not, though if it crosses your mind then seriously consider whether you should, as there are risks. 

25 free MoneySaving apps to download to your smartphone

If you've got a smartphone, it can be a great tool for saving (and making) money. Here's a rundown of some of the best free MoneySaving apps, many of which can be found on MSE team members' phones. 

10 novel MoneySaving tricks to get must-read Kindle books for FREE (or just 99p)

Amazon is heaving with Kindle books that are permanently free or 99p. Yet these cheap titles may not always match your virtual to-read pile. In fact, you often have to wade through a lot of very average books to find the good ones. And if you pay full-price for Kindle books and devour several a month, the cost can soon stack up. 

A MoneySavingIdiot claims for a train delay

My name is Kelvin, I'm a features writer at MoneySavingExpert.com... and I'm an idiot with money. I've no excuse – after all, I write for the UK's biggest consumer website. But sadly, while I play a part in helping people save every day using MSE, my personal relationship with cash is a mix of fleeting highs and lingering regret.