You prevent scammers (as much as possible) by building feedback to give yourself a professional reputation, by writing your description with good grammar and spelling so you don't look stupid, and by using clear detailed pictures.
Then you use your Seller preferences to Block bidders who are in places you don't want to ship (Africa, Italy, Brazil - all for different reasons). Basically stick with USA and Canada.\
You also Block bidders who do not have an active Paypal account. This stops bidders who just signed up and/or who do not qualify for a bank account or credit card.
You can list at Fixed Price/Paypal Required/ Immediate Payment Required. This is not a free listing, btw.
Scams come under two basic headings. Item Not Received and Item Not As Described.
INR are prevented by using Delivery /Signature Confirmation of delivery. Basically this is Expedited Parcel and we get a 20-25% discount from PO counter prices if we buy the shipping label through PP. This service is also insured against loss or damage in transit by Canada Post.
In an NAD dispute, the buyer must return the unwanted item to the seller with the same Delivery Confirmation to get a refund.
None of these is perfect, of course. But cumulatively, they give a lot of protection. Most of the problems sellers whine about are because they did not follow those guidelines (and ran into a scammer, but most of your customers are as honest as you are.)
Have you considered Kijiji and Craigslist?
