How to make a site that operates in the following way…

This is a strange request, but I need help setting up a site that can do the following with a variation of plugins, etc.

My idea: I want to build a site that allows visitors two options: buy and sell. They can then click buy, fill out a quick form, and it produces results of all the sellers. Secondly, I want an option for Sell that users can fill out a form and sell something and it is entered into the database.

Now my original idea is to use Contact Form 7 to allow users to sell something, then use the CFDB plugin so it is stored into a database. And then finally for the Buy page, users fill out a form of the filters of what they want to buy, it manipulates the shortcode of the CFDB plugin, and displays a filtered result.

Everything above I know will work for what I want, but where it gets tricky is having that same user being able to delete their post. I know I can send them an email for verification, but maybe include a unique link to delete/edit their post.

I understand that there are “classifieds” themes and plugins that do this, but the items being sold/bought are Tickets for a specific venue. So I only need simple parameter such as Name, email, Asking Price, etc.

I want to make the website smooth and simple. Simply, put two large buttons on the site labeled Buy and Sell. Both point to a form, and then the Buy displays the filtered results (in a smooth, eye-candy display).

If anyone has any ideas, that would be greatly appreciated. I know some PHP as well as html and css. But creating this from scratch would be time-consuming and something as simple as this could hopefully be done easily using various plugins and a CMS.

Thanks!!