Usually, the sales season of Hong Kong in winter starts at from every Dec, espcially around Christmas and New Year's Day. However, I think you could find some at the end of Nov. Please go to these large shopping plazas which will supply very satisfied discounted price.
Ps: when you arrive at HK Airport, please collet these promotion brochure at the Travelers' Service Center. There will be the latest sales info and coupons attached.