Without a good credit history, you will probably not find any lender that is prepared to lend at an affordable price.
Better option is never to buy on credit. Its an expensive way of getting something, especially if it's something you cannot afford.
If you have an existing phone, you can get a giffgaff sim and use it in your phone (you may need to get the phone unlocked from the previous network). Then pay only for your minutes, data and texts each month -- see the goodybags at https://giffgaff.com/buy/goodybag -- they can be bought either with a payment card, paypal or giffgaff vouchers from supermarkets.
Then, put aside the money that you would be paying on loan repayments -- eventually you'll have the money to buy a new phone outright and it will be a lot cheaper than if you had bought it with a loan.
If you don't have a phone, then try buying a used one -- preferably from a friend you trust who has just bought a new one and still has a wholly-owned phone no longer in use. Again, you'll be able to use it with a giffgaff sim, but make sure it's unlocked.
But if you really must get a loan, maybe try your bank ?