Oh I posted this on another thread yesterday so I'll post it here too in case it's helpful for anyone. x
Not really side hustles and none of these are gonna make one a millionaire overnight but the pennies all add up over time and can help a little in keeping costs elsewhere down and that.
A) Survey sites - sign up then survey links are emailed, paid once approved. Can pay well and soon mounts up.
Populus Live (you're sent a cheque/BAC once you hit £50).
Prolific
Panelbase
Opinion Outpost
B) Cashback sites - cashback on online shopping, services, etc.
Topcashback
Quidco
C) Cashback sites/apps (1) - buy specific products, upload receipt then refunded all/percentage of price.
Free food!!
Shopmium
Checkoutsmart
Clicksnap (can't use same receipt on both Checkoutsmart & Clicksnap - part of same company).
GreenJinn
D) Cashback apps (2) - scan receipts generally. Earns pennies.
Shoppix
Receipt Hog
Huyu
Snapmyeats
Storerewards
That's all I can think of for now.
ETA: There are also sites where you can read magazines and newspapers for free instead of spending like a fiver on a glossy. I'll update if I find links. x