A USB powerbank (as in this thread), for £1 or £2 for a better one. Sounds like very good value to me, and I'm tempted to buy them.
Anything with a Li-ion cell in it for that price is asking for trouble.
FYI, if you search Taobao, you will have a hard time to source the battery cell alone for that price, and that's even from China directly.
I have checked (watched), BigCliveDotComs video reviews of other (Not watched much of USB power bank video, yet), PoundLand stuff. The other items seem pretty reasonable for £1 (or £2), such as USB chargers.
PoundLand buy things in massive bulk quantities, and negotiate hard to get the best prices. If they can't get good prices, they pass (don't buy) on that item/seller and carry on finding other "bargain" items.
But you still have a valid point.
For my "main" USB powerbank, I've bought an "expensive" one, which had very good reviews on Amazon.
It's worth it, for when I'm out and about, and need a decent power source. Or even for when at home use and I don't( want to) or can't plug something into the mains.
But £1/£2 USB power banks, tempting, for powering quick projects and/or messing around and stuff. At that price, you can just bin it, when/if it eventually breaks.