How cheap does wine have to be before it is socially unacceptable to serve to guests?
With the discounting that goes on over summer, wine that won't make every guest suddenly claim pregnancy can be bought for about $11.
However, a glance at the cavernous hole above the "Special - $8" sign in the supermarket wine section is evidence this guideline can and will be stretched.
If buying from your local corner shop, at least a few dollars should be added to the $11 minimum.
If you must go below, there are options.