2 fones 101% totally free rental n free fone. Other fone claim back 71% of rental & free fone. All done online no need to post bills like a couple of years back - blimey mustn't forget to claim in time
I ended up getting a nice dual sim Moto-G xt1068 expensive but 71% cashback. Then I saw nokia 530 free fone and 101% cashback and got me one and my son one 300min,250mb,5k txt £7:50
Mobiles.co.uk & mobilephonesdirect.co.uk - when you sign up for fone n 24month contract, some fones on some providers have cashback offers by redemption - very yanky
Anyway - did mobiles.co.uk x 2 cheapo samsung Galaxy Y's 2.5 years ago and got back aprox 85-90% of monthly bills