There's quite a few shops around 东四.. I would recommend In-House/Life Force skateshop, it's on mao'er hutong near nanlouguxiang... although they might be out of decks right now... but they got their own brand bearings, wheels, trucks, and hardware all
of which are fairly descent quality and very well priced. If you want imports, which are more expensive, you could try Tour or Eternal skateshops... both of which are around the area... if you want to go to Life force I can probably help you get a better price,
so let me know.