We are an India based web agency, and have a product that will be of help to you in opening your classified ad.
Our product YoTree is a ready-made website script for starting online platforms like Olx & quickr quickly. It is, you can say, Shopify/Magento for classified websites.
A piece of advice here as well. If you are planning to build a classified website from the ground up, we would advise you to go otherwise. Using a technology solution like YoTree, will save lots of time, efforts, and money as well. Plus, without prior experience in the industry & knowing how ecommerce businesses work (I am assuming it from your question), it will be very difficult for you to build a good-enough classified website with features that gives you the potential of beating the existing competitors.
Our packages starts at $499 (one-time payment), and you can learn more about YoTree here. http://www.fatbit.com/classified-ads-website-script.html
Good luck with your business.