Ryanair and easyJet are famous for purse-friendly plane tickets — especially if you’re organised enough to book well in advance. But if there’s one thing both airlines aren’t famous for, it’s generous free hand luggage allowances.

Even though Ryanair increased its luggage allowance at the back end of the year, passengers still have a pretty small free bag size to work with. And, as frequent flyers know all too well, if your bag is even a little too big, you could be hit with a last-minute charge at the airport. Not exactly the cheery start to a holiday.

The easiest way to avoid that dreaded check-in desk moment? Make sure your bag is the right size before you even leave the house. Luckily, we’ve found one that fits the luggage rules for both airlines, and right now it’s half price as part of the Amazon spring sale (known as Amazon Spring Deal Days).

Ryanair’s luggage allowance recently increased from 40 x 20 x 25cm to 40 x 30 x 20cm. On paper, that might sound like a welcome boost, but in reality, it’s a little less dramatic. You lose 10cm in length one way, but gain an extra 5cm the other way — so in practical terms, there isn’t a huge amount of extra wiggle room. Of course, you can bring more luggage if you pay for Priority, but that means adding to the cost of your trip.

easyJet is slightly more generous. Its free hand luggage allowance is a maximum of 45 x 36 x 20cm (including handles and wheels), and the bag must fit under the seat in front. It can weigh up to 15kg, as long as you’re able to lift it yourself. If it goes over those dimensions, you could be charged a fee of up to £48.

That’s where the expandable Hayayu bag from Amazon comes in.

Normally priced at £23.99, the bag has been discounted by more than half in some colours during the sale. At the time of writing, the best deals are on the grey and cream versions. The grey bag, usually £23.99, is now just £11.98 — a 50% saving. The cream colour is even cheaper. Usually £23.99, it’s now just £10.19, which is a saving of 56%.

The bag measures 40 x 28 x 20cm, making it just the right size for Ryanair’s new luggage allowance. It also has the added bonus of an expandable section that lets it stretch to meet easyJet’s slightly more generous guidelines of 45 x 20 x 36cm.

But we didn’t just want to take the measurements at face value — we wanted to see how it performed in the real world. Since Ryanair’s rules are the strictest, we enlisted Dublin-based reporter Fran to put the bag to the test on one of their flights. You can read Fran’s full in-depth review here.

She’s tried several bags over time while frequently commuting between her home and London with Ryanair, and she says the Hayayu holdall is her favourite so far, thanks to its versatility. The standout feature, she said, is the expandable compartment. “I imagine this will come in extremely handy on an upcoming holiday,” she said.

Based on previous customer reviews, the bag currently holds a rating of 4.6 out of five stars on Amazon.

One of the first things Fran liked was its stylish appearance. It comes in a choice of colours — green, grey, white, blue, black and pink. Fran chose the pale pink version, although in hindsight she admits the black might be the most practical option for keeping it looking clean while travelling.

The second thing that caught her attention was just how roomy it looked. “When the bag arrived, I measured it because it looked much larger than the bags I had previously tested,” she said. “I was concerned that it might be too big, but I was pleasantly surprised to discover that it met Ryanair’s requirements.”

Despite fitting the airline’s compact measurements, Fran says the holdall is surprisingly spacious. Her mission was to pack everything she needed for an overnight work trip.

“Of course, I needed my laptop, which at 15.6” has caused me trouble with carry-on bags before, as they all seem to be designed for a 13.3” machine,” she said.

In fact, of all the bags Fran tested, this was the only one that comfortably fit her slightly larger laptop, too.

As is often the case with Amazon sales, though, the discount could change — or disappear altogether — so anyone tempted may want to snap it up sooner rather than later.