When you’re selling items it’s just as easy to list on two sites as it is to list on one. They both require the same information for listing: UPC/ISBN number, an item description, the quality rating (New, Like New, Very Good, etc.) and your selling price. As mentioned in my post Tips for Selling on Half.com or Amazon, you’ll want to research the going rates for your items on both sites to see if it’s worth your while to sell on either site, keeping in mind selling fees charged by both. Both sites charge nothing to list items so it doesn’t hurt to list on both.
If you have a number of items to sell and you think they’ll do well on Amazon you have the option to use Fulfillment by Amazon (FBA). With this option you ship all the items you’re selling directly to Amazon. They store them in their vast warehouse and ship them for you when they sell. One of the benefits of doing this is that items that are fulfilled by Amazon qualify for free super saver shipping and free Prime shipping. This gives your items an advantage over others since they’ll be displayed on the item page with a $0 for the shipping cost, moving your item up in the list.
The cons to using FBA are: 1) you are stuck selling your items at Amazon 2) you have to pay to ship your items to Amazon 3) you won’t get credit for shipping costs and 4) Amazon will charge you a picking fee for each item ordered, an order handling charge and a weight handling charge. You may also have to pay for storage costs if your items don’t sell quickly. In order to make a profit with FBA you have to list your item for a higher price which will probably negate the benefit of offering free shipping. Check out this page for more info on the FBA Program fees.
In the end, your best bet to make some money is to list your items on both sites, Amazon and Half. And if you don’t get any bites after a couple of months consider dropping your price.