Decent cheap luggage - from £8.99 at poundstretcher, picked mine up in store, but appears online.

Just picked up the medium size (£11.99) which fits my airlines cabin baggage restrictions (these vary between airlines so please check yours before purchase).

Seemed like a good price for a wheeled suitcase that fits in the overhead bins. The smaller one (£8.99) obviously fits too but you would waste some of your size allowance.

Mine has zip pockets on the front which is handy for headphones etc. check this before you buy as weirdly some of the colour options lack the front pockets.

Hope this is of use to people hoping for a cheap getaway.

EDIT:
Size of small suitcase (cm): 51 X 36 X 17
Weight: 2.28kg

Size of medium suitcase (cm): 54 X 40.5 X 20
Weight: 2.65kg