Contract Law Khatam Hota Hain: Consideration aur Free Gifts

Ye to main samajh nahi paata, bhai. Free gifts to consider kyon nahi hota? Maine socha ki jo bhi gift de raha ho, woh bas ek favor karta hai hi nahi. Lekin ab main yahan padh raha hoon ki yeh free gifts bhi consideration ke under aate hain. Agar koi mere paas ek free book de raha hai, toh main uska consideration kya de sakta hoon? Uske liye meri koi duty nahi hai. Mujhe lagta hai ki yeh koi confusion hai. To kya hai yeh sahi jankari? Please clarify karein.