To Buy: 
Unshelled peanuts should have clean, unbroken shells and should not rattle when shaken. There are hundreds of ways to buy peanuts - roasted, dry roasted, salted, etc.  
Best buy raw and roast and salt them yourself. Buy whole peanuts and chop them in a food processor rather than buy them from the supermarket pre-chopped. 
To Store: 
Store in an airtight container in the fridge. Unshelled peanuts will keep for up to 8 months in the fridge while shelled peanuts will keep for three months. 
Tips & Tricks: 
Peanuts make an ideal snack for sustained energy if you have a long wait between meals - they are high in fat, a good source of protein with a low GI. 
Cooking Tips: 
Chopped peanuts are delicious in Asian stir-fries and  sprinkled over desserts.