Brand name spoofing/phishing:
You get an email that claims to be from Quikr, Western Union, or another company and offers buyer protection or an online payment system. These emails will typically request that you send money via this site or provide personal information. Quikr and most other companies will never send out such emails. If you send money via these sites you are likely sending money to the fraudsters.
A buyer or seller will send you a cheque and then ask for money to be returned to them. Often the cheque will bounce and you will have lost all money you sent to the other party.
Payment for brokerage/importing:
A seller claims that there are brokerage fees, import duties, or other such fees required to get an item into India. Do not pay such fees, as you will most often never get the product and will have lost any money you paid. Again to remind you : Quikr is designed for local, in-person trading .
Fake escrow sites:
A buyer or seller suggests using an escrow service to complete the transaction. Often these escrow web sites are run by fraudsters (even though they may look "official") and they will take your money and never send you the product.
Work from home:
Many work from home offers are "pyramid schemes" which require you to recruit other members in order to get paid. For example, an Ad may say that you can make $100 or few thousand rupees an hour by stuffing envelopes. But to make that money, you need to sell the system to others.
You get an email saying that your help is needed to help take money out of a country and that you will be paid a commission for your help. Finally, they will ask you for money to help them take the large amount of money out of the country and once you pay you will never hear from them again.