I bought this Aukey 20,000 mAh Dual USB and Lightning power bank from Amazon UK. I paid £21.49, but it normally seems to be available for between £20 and £23. It doesn’t have many fancy features, it’s brick shaped and heavy, but it is a solid powerbank with an impressive capacity for a good price. Recommended.
This Power Geek “Awesome” 2200 mAh power bank came from Poundland for the princely sum of £2. They do a 4000mAh version for £5 too. It’s interesting if you need to power a very low current device because it doesn’t cut the power off under low load like most power banks do, but it was unable to sustain 1 amp for the whole discharge test. For light loads like bluetooth headphones it’s good value, but look elsewhere if you need to charge a smartphone.
I bought this Juice Long Weekender Dual USB 10,050 mAh power bank from Sainsbury’s for £20. Normal retail price appears to be £30. I’m not a fan of the fingerprint magnet mirrored part of the case, but it meets the claimed specifications and seems to be of a reasonable quality. Not bad for £20 if you need something you can pick up today.