We recommend that everyone start their own stores as soon as possible! From our many years of testing and experimentation, Oscommerce is the most friendly PHP shopping cart in the world. You can have a store up in just hours. Most importantly, it's 100% free through the open source GNU project http://www.oscommerce.com.
Getting traffic to your site is not so easy. It's best to first start by working on your meta tag description and keywords, writing descriptive information about your products and services while insuring that your keywords are repeated a few times within your content. If you have previously written any articles or blogs pertaining to your products or not, create links to and from the articles while always including your domain name on offsite pages and all emails within your signature.
Oscommerce is not search engine friendly by default, so, you will need to add plug-in(s) (freely distributed on the contributions link requiring some programming experience) Then, after you've added all your products with full descriptions, start using Google's Webmaster tools to validate your website and add maps (read Google's information for additional details). Then, start posting your site freely to other major search engines such as Altavista, Yahoo, etc. You also have the option of using Google's adwords ($$$). Although we did not see a significant increase in sales, the utilities they provide for website traffic analysis are beyond anything we've ever seen.
Additionally, once you're completely up and running with all products uploaded, use Google's new Base http://base.google.com. For free, you can upload all your products via special tab delimited format (free oscommerce contributions available). We have received significant sales through this channel alone, and it's definitely worth the effort!
Trust and safety are most important for buyers. They want to feel safe. If accepting credit cards, you "must" have an SSL certificate on your server. Other options are Google Checkout (non-Paypal non-Ebay). When accepting Google Checkout, you do not need an SSL certificate, in addition, it's safer than Paypal (in our opinion) for the seller and buyer. Using Google Checkout for two months now, we have not had a single fraudulent chargeback. However, with Paypal our losses due to illegal chargebacks are unimaginable. Nevertheless, you will most likely want to accept both, but cautiously watch all orders from Paypal. They perform little to no screening of buyers - only sellers. For example, payments from a buyer in France requesting shipment to a hotel in Hong Kong are very common. You don't want to lose your product and profit to fraudulent buyers.
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