1) Yes it's the cheapest so far but the question is whether it's the best plan for your usage. Is there enough minutes and text for your usage otherwise you could end up paying a lot more than choosing the best plan to suit your needs.

2) Yes, according a few posts earlier.

3) This usually applies to PAYG (non contract) plans. Don't worry with T-Mobile you get a fair usage of 1GB per month.

4) Your phone is covered by warranty. I believe it's two years with Nokia (long time ago it was one year). You can get in touch with your operator or Nokia for any repairs. Remember this does not cover accidental damage such as liquid damage, cracked screens etc.

You can insure your phone which cost about £5 - £10 /month but make sure you read the contract and small print because some of them are no better than the warranty which already covers the phone from manufacturers defects. i.e. doens't cover accidental damage or negligence. Doesn't cover lost or stolen etc.

5) No, its yours to keep or if you're like me, I always sell it after a year (12 months contract) so recoup about 50-70% of the value.Then I buy another top notch phone on 12-months contract.