I suggest you purchase cell phone from normal electronic stores, such as Suning and Gome. I know three branch stores of Suning. Here are their address:
84 Nanyang Road (at the crossing of Nanyang Road and Yuejin Road)
56 Wenhua Road (at the crossing of Wenhua Road and Nongye Road)
26 Mianfang Road (at the crossing of Mianfang Road and Songshan Road)
Nowadays, cellphones is getting cheaper and cheaper. If you don't need a cellphone with too many functions, I think you can buy Nokia 2610, 3230 or 6120C. 3230 and 6120 support Bluetooth connection mode.