Flipkart is offering an exchange offer worth Rs18,000 on old smartphones during the Big Shopping Days sale. Flipkart.com is holding a three day sale (7-9 December) called Big Shopping Days sale offering direct discounts, exchange offers, cashbacks on credit cards and buyback offers on hundreds of gadgets. Flipkart is also offering an exchange offer worth Rs18,000 on old smartphones. There is an exchange offer worth Rs18,000 on older smartphones, but it's valid only on high-end models such as iPhone 7 Plus. There is a bank offer too with 10% discount on SBI credit cards and an exchange offer of up to Rs22,000.