Ebuyer.com has this palm-size Motorola C118 payg on Virgin network (with £5 credit) for £19.69 inc Free delivery.
Mobile cost is just £14.69 after savings. Go through Quidco for a further 1.5% in cashback.
Pretty basic DUALBAND palm-size mobile with convenient features including: Monophonic ringtones, Vibrating alert, Stand by time: up to 450h, Talk time: 11h 40m, Compact form & Pre-loaded games. Outstanding battery performance.