Cheapest sim free I can find is £300 so approx £110 saving on that price.
119.99 up front then £3 a month for length of contract is the tariff you need to select. You might need to click show more to find this tariff.
You can choose any tariff this time so I would advise going or the 500Mb plan with 119.99 up front but the general jist of o2 refresh deals applies:
1.Receive device in the post / Collect your phone in store.
2.Request unlock - most succesful way I have seen to do this is through the my o2 website or app
3.Once unlock code is received unlock your phone (approx 48 hours) - some people move to step 4 straight away as soon as requesting the unlock code but I have waited when doing it in the past.
4.Ring up and pay off the device plan but cancel the airtime contract saying you think the device plan is great value but you have seen better airtime deals elsewhere. This is the most difficult step dependant upon who you talk to at o2 and if they understand the o2 refresh deal properly or not.
At worse you might get charged for 2-3 days of the airtime contract whilst you get the unlock code by waiting - which should be under £3 on the 500Mb plan
Sometimes the process has been known to go wrong and you do have to go through getting a refund but this has happened to me once in four deals (I change phones a lot) but I managed to get the money refunded back to my account before I was billed so I didn't get charged the full airtime contract and then have to wait to get my money back.
I know this phone isn't for everyone especially since they removed the dust and waterproofing but I am after a small (fairly) powerful android phone and this seems to be the only one that even comes close to being that. All the reviews say the 650 processor is fine even for top games due to the 1280 x 720 res on the screen. I had a z5 compzct but sent it back due to the overheating issues which is why I assume they have gone for a lower spec processor this time.