To Buy: 
Buy from health food or Asian stores in packets. Agar can be bought in bars, flakes or powder form.  
To Store: 
Store once opened in an airtight container in a cupboard. It will keep for up to 8 months. 
Tips & Tricks: 
One agar bar is equal to four tablespoons of flakes or two teaspoons of powder. Generally if a recipe calls for 1 spoon of gelatine you substitute with 1 spoon agar.  Agar Agar will not set in vinegar, or foods rich in oxalic acid like rhubarb, spinach or chocolate.
Caution- People with weak digestion and loose or watery stools should use agar agar sparingly.
Cooking Tips: 
One bar or its equivalent will gel two cups of liquid. Agar needs to simmer for a while to dissolve. Refrigerate until it becomes hard.