One of the more innovative online earning opportunities come from Roamler. This is an app which can be downloaded onto a smartphone.

From there you are set various tasks.  The original tasks are unpaid and simply to test your ability.  You then move up levels and onto different forms of paid tasks of a mystery shopper style.  These include having to visit supermarkets to take pictures of fruit/flower stands & answering 2 or 3 simple questions about the layout and freshness. Other tasks involve going to pubs and asking which type of beer they'd recommend.

Overall, its a lot more interesting than sitting on a computer clicking repeatedly and can sometimes be done during your lunch time or on way to or from work.

Tasks generally pay between £2 and £9. You can cash out via Paypal at any point.

ROAMLER

Earning money online comes with a stigma attached that it's all scams and pyramid schemes. There are many good and reputable sites available too though.

I have personally been caught out twice. A site called Can't Beat Free disappeared leaving people owed money and gift cards. Another site called Rewarding Ways waits til people reach payout level and accuses them of having several accounts or using a proxy IP address. 

Sites I can verify that pay out:

Swagbucks

Gifthulk

Zoombucks

Irazoo

Global test market

Onepoll

Neobux

Clixsense

Inbox Pounds

Opinion Outpost

Pinecone

Panelbase

Roamler