The majority of transactions on eBay go smoothly and without incident, but there is always someone willing to step outside of the rules to save a buck or make more money from their items. Here are some scams to avoid.

• Shill Bidding

This is a rather basic one where a seller uses other id’s or has friends raise the number of bids and value of an item. This has been going on for ever in car auctions where a “ shiller “ in the audience will bid against someone who is interested in a vehicle to drive the price up, and is just as popular with online auctions. Watch for recurring user id’s on a sellers bids or for sellers who routinely bid - but don’t win on each others auctions.

• Bid Shielding

This one involves a ring of bidders who target an item they want and put in multiple bids. One for the price they want, and then a series of bids that inflate the item to scare off any other bidders. Moments before the bidding ends, the high bidders retract their bids and the low bid wins the auction. Watch for bidders who have a history of retracting bids.

• Switch and Return

Some dishonest buyers will purchase your item, receive it and then return it.   The scam: The item they return is not yours but theirs and is an attempt to upgrade their item for free at your expense. Watch for bidders who are overly interested in your return policy.

• Fakes and Reproductions

It’s a mistake to think that a certificate of authenticity is proof that an item is real. Think about it, if a seller is willing to misrepresent a fake item as real, then what is the big deal of throwing in an authentic looking certificate verifying the value of the property. Watch out for items that are scarce suddenly appearing in mint condition online. Also watch for any type of comment in the description that gives the seller an out if the product turns out to be fake like “ To my knowledge “ or “ I think “

In the end, if you think you have spotted a crook either in a seller or a buyer, report the incident to eBay.