Yes they can which is what I am planning to do and put my EE data sim in it.
Unlock codes are 99p from Ebay or try this https://huaweiunlockcalculator.com/v201-huawei-unlock-calculator-v3 , saw it on another post and not tried it yet as I have yet to collect from store.

On a rolling contract though wouldn't really make any difference on rolling or PAYG really though

it's now showing £19.99

In stock, closest to London is Sydenham
London, SE26 4PU

Nearest one in stock for me is over 35 miles away :disappointed:

Don't trust PC Thieves - i spoke to customer services about the osprey they had and was assured i could but it with no contract. drive 40 miles to get one only to be told by the obnoxious manager in Stockport that i couldn't do that. I tried at another store, and was going to sign up for a month to cancel but their useless systems wouldn't let me as i already had an EE contract. PC world wasted about 5 hours of my life.

Got one of these and unlocked off eBay a while back, used it more as a hub for the kids to connect their tables to to share content while driving. 3G bit is pointless really unless you need the data download but my phone has this already just the kids wifi tablets do not and YouTube is crap on 3G,which is what their internet comprises of. 4G may be better for this purpose especially if sharing with tablets.

A few benefits for me...

1) It saves your phone battery
2) You can use a different network that has better data deals (inc roaming data) without switching sims in your phone.

I need one as decided to wash my 3 one.

We used one with a three sim in it in france so none of us had to pay for euro data. Came unlocked out of the box

what's the benefit of these over tethering?

Good deal but seems out of stock in the London area.

What's battery life like on these?

none in sussex

The wild geese have already flown to their summer living grounds.

3gb for £15 a month is pretty crap. I got an EE deal last year for 30day rolling at currys where you received 20gb then EE offered me a £5 discount and upped the data to 30gb all for £10 a month now

This one's only 3G. Better going for the 4G version. I got one off eBay cheap, and when used with a LTE antenna works extremely well.

can these be unlocked to any network ?

find one and see - 97p usually means wild geese

Also appears to require a contract (albeit a short one).