In Australia, an isolated shop, usually  in residential areas and often set up in what used to be a house, selling:

milk
bread
pet food
washing detergent
nappies
sanitary products
disposable razors
ball point pens
sticky tape
gift wrap
postage stamps
chocolate in bar, block, or gift-box form
sweets
crisps
cigarettes
lemonade and other softdrinks
pies, pasties and sausage rolls
magazines
and often newspapers.

Milk Bars are generally family businesses.
No true Milk Bar is a part of a franchise or chain, and in fact it is the chain "convenience stores" such as 7-eleven and FoodPlus, along with 24 hour supermarkets, which are driving many Milk Bars out of business.

In New Zealand, Milk Bars are called Dairys.