Question

aisi kon sa cheez hai jo aadmi kharida to wo pahanta nahi aur pahanta hai to karidhta nahi

Answer 1

नमस्कार मित्र,

उपर्युक्त प्रश्न का उत्तर है 'कफन'

Answer 2

Thanks for the question!
MrDunno has rightly told that kafan ( shroud ) is one thing that a person does not buy but wears it and the one who buys does not wear it! 

There can be other things similar that one may buy and not wear and viceversa. 
The other thing is called Baby Diapers :D like huggies, pampers etc

Hope it helped you