When you're in a pinch and realise at the last minute that you're missing salt, you don't have to run out to the market if you have some lemons or lemon juice on hand. Secret Tips from the Yumiverse offers this and other handy common cooking substitutions.
When you're out of salt, use half as much lemon juice in your dish.
Also, you might run out of sugar often, but that's more easily replaced with an ingredient less often used up: icing sugar (substitute 1 and 3/4 cup of icing sugar for every 1 cup of regular sugar). Other substitutions suggested are great for allergy sufferers, such as replacements for eggs.
Check out the cooking and baking substitutions via the link below.
13 Handy Cooking and Baking Substitutions for Missing Ingredients [Secret Tips from the Yumiverse]