Fiverr: Israeli-based Fivver was started in 2010 by Shal Wininger and Micha Kaufam. It's a great resource for selling just about any service online. You can offer gigs as low as $5 but also get paid much more for upgrades and add-ons. There are plenty of providers earning 6 figures on Fiverr so it's definitely a worthwhile cause for generating a healthy income. Just ensure that you provide some serious value.
Research selling prices of items similar to yours. Look up completed sales or current listings of items similar to yours. Find the high- and low-end prices, and price your object around the median price level. If you want your item to sell quickly, price it at the low end. The condition of the item also affects the price. Items in poorer condition should be priced at the lower end. Also, consider how many listings there already are of items similar to yours. If many similar items will be competing with yours, you may have to set the price lower to get the sale.