There are some useful groups on Whatsapp and Facebook where people sell there items when moving. As Hong Kong is quite a transient place you can often get some great deals. Please note that as with all online groups there are scammers - agree to a face to face meet to purchase items.
Here are a few to search for:
Discovery Bay
Whatsapp:
There are also additional Whatsapp groups for housing areas once you move in
Facebook:
DB Matters (And so do your opinions)
Discovery Bay (HONG KONG) BuySellSwap (residents of Discovery Bay Only)
Hong Kong
Hong Kong - Buy - Sell - Rent - (Leaving/ Moving/ Second-hand Goods)
New to HKG? Even though they have moms in the title the groups are open to all newcomers.