I'm am interested in expanding my Liquor Display business into an
online bar products website.
I need to know how to go about getting wholesale bar products. Do I
need to contact different manufacturers  for every product available
or is there a way to get everything from one place?

If you're a newcomer,you should take experience, operating
money,risks,etc into consideration.I suggest that you'd better get all
the bar products from the wholesale place(It's not difficult to find
these place in many middle or big cities). May be you can make less
profits than you do from the manufacturers,but you'll take less
risks,spend less money and your store can open easily at a short time.
After a period of operation,maybe you've had much experience and
reputation,if you want to make more profits,you can contact different
manufacturers directly.