How easy is Drupal for E-Commerce?
You don't need any coding to achieve this functionality, you can just go with Commerce and using Drupal's built-in roles, manage who has the permission to create content (items to sell) and who has the permission to buy it.

for the search aspect of it, I suggest trying Search API, which gives you facet like filtering feature (Like ebay), also you might wanna check Apache Solr for faster indexing