Suggest you go to Dahongmen at South 3rd Ring Road and there are also buildings and markets near the Zoo. I can find what you want there.

Most foreign travelers do like to purchase cheap cloth in the Silk Market, so famous during travelers. As for locals, they always go to the wholesale markets around Beijing Zoo, but you should be good at bargaining.
Good suitcases could be found at any stores or supermarket, such as Wal-mart, Carrefour and Lotus Supercenter.

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