Google Pixel 2 64GB, no bloatware from £580 if you shop around. BT SIM only plan from £6 / month if you have BT Broadband. The only question now is what to spend the change on.
Everyone has different needs and views on what is expensive or not. If you want to have a phone on contract then they are all expensive. I find BT’s sim only deals are excellent value (though I own my own phone) but I don’t use a huge amount on calls or data so I think £5 per month is cheap. Clearly if you want, rather than need, the latest iteration of phone and a huge calls and data package then all operators are expensive and you just choose the one that suits your needs best.
Contracts are usually more expensive simply because you are paying for the privilige of spreading the cost over 1 or 2 years, or in the case of the newest MVNO, 18 or 30 months.
The last time that I looked BT were competitively priced when it came to contracts.