One option could be to look at major online retailers such as Walmart's website or Best Buy. Additionally, some independent movie stores might carry it. Another possibility is to search on second-hand marketplaces like Craigslist.
The best places to start your search for a 'A Chinese Ghost Story' DVD are big-box stores like Target or online marketplaces like Alibaba. You could also try reaching out to local video rental shops, although they might be less common these days.